“kossori・hisoka ni”: Secretly / Quietly / Inwardly [JLPT N1]

Content by NTJ Kuma · Nihongo to Japan editorial team · Updated July 27, 2026

Adverbs for doing something secretly, without others knowing

「こっそり／ひそかに決意する」 — a stealthy action vs an inner, secret resolve

To say “do something secretly, in stealth,” 「子供たちは親に隠れて、こっそりお菓子を食べた」 (hiding from their parents, the children secretly ate sweets) — 「こっそり・ひそかに」 both express doing something “without letting others know,” yet with different feels: こっそり = secretly (a concrete stealthy action, colloquial); ひそかに = in secret, inwardly (more written, can be internal). This guide covers the division of labor, which to use for inner feelings, and separating them from 「こそこそ／に内緒で.」

Core: proceeding undetected — a concrete action vs an inner secret

Both are adverbs for doing something “without letting others know, in secret,” but with different feels:

① こっそり = secretly (a concrete stealthy action, colloquial, mimetic, neutral):

• 会議中に、こっそりスマホを見た (during the meeting, I secretly checked my phone).
• 誰にも見られないよう、こっそり部屋を抜け出した (so no one would see, I slipped out of the room).

② ひそかに = in secret, privately, inwardly (more written, can be internal):

• 彼はひそかに、再挑戦を決意していた (he had inwardly resolved to try again).
• その計画は、ひそかに進められていた (the plan was being advanced in secret).

Feel: the core for both is “out of sight, quietly,” but — 「こっそり」 leans a concrete stealthy action (slipping out, sneaking a bite, peeking), colloquial and vivid; 「ひそかに」 leans in-secret／inwardly, more written, and can mean “an inner secret” (inwardly resolve, inwardly expect). In English: こっそり = “secretly, stealthily”; ひそかに = “in secret, privately, inwardly.”

Attachment rules

Examples in context

• 母に内緒で、こっそりお小遣いを貯めている。(Hiding it from my mother, I'm secretly saving my allowance.)
• 抜き足差し足で、こっそり近づいた。(On tiptoe, I stealthily approached.)
• 彼女は長年、ひそかに彼に思いを寄せていた。(For years, she inwardly carried feelings for him.)
• 政府はひそかに、その計画を練っていた。(The government was secretly hatching that plan.)
• 心の中で、ひそかに成功を願っていた。(In my heart, I secretly wished for success.)

⚠️ Easy traps to avoid

① こっそり leans ‘a concrete stealthy action' (colloquial); ひそかに leans ‘in secret／inwardly' (written). This is the two's core division. 「こっそり」 = secretly (a concrete stealthy action, colloquial, mimetic, neutral): it leans “a concrete, visible stealthy action” — slipping out, sneaking a bite, peeking, hiding — colloquial and vivid: こっそり抜け出す (slip out), こっそり覗く (peek), こっそり隠す (secretly hide). It mostly depicts “a concrete stealthy ‘action.'” 「ひそかに」 = in secret, privately, inwardly (more written, can be internal): it leans “things advanced in secret” or “an inner secret feeling,” more written: ひそかに計画を進める (advance a plan in secret), ひそかに決意する (inwardly resolve), ひそかに期待する (inwardly expect). Test: to say “(concretely) do some stealthy action” (slip out／sneak a bite) → こっそり (colloquial); to say “in secret (advancing)／inwardly (a feeling)” → ひそかに (written).

② ⭐For inner feelings (inwardly expect／respect) use 「ひそかに,」 not 「こっそり.」 This is the most error-prone point. To express “an inner secret feeling” — inwardly expect, inwardly respect, inwardly adore, inwardly resolve — use 「ひそかに」 (inwardly), not 「こっそり」 (こっそり is mostly a concrete action): ✗ こっそり尊敬する → ✓ ひそかに尊敬する (inwardly respect), ✗ こっそり期待する → ✓ ひそかに期待する (inwardly expect), ひそかに憧れる (inwardly yearn). Because 「こっそり」 is “(physically) doing some stealthy action,” while “inwardly respect／expect” is “(inwardly) quietly holding some feeling,” not a concrete action, so use 「ひそかに.」 Test: an inner feeling quietly held (respect／expectation／yearning／resolve) → ひそかに; a concrete stealthy action (slip／eat／peek) → こっそり.

③ Division of labor with 「こそこそ (pejorative sneaking)／黙って／に内緒で.」 These all relate to “secretly, hiding from,” but differ in feel. 「こっそり／ひそかに」 = secretly／in secret (neutral, just not making it known): こっそり抜け出す (a neutral slipping out). 「こそこそ」 = sneakily, furtively (a negative, guilty, sneaking pejorative): こそこそ話す (whisper furtively — with a “guilty, not aboveboard” pejorative), 陰でこそこそする (be up to something behind the scenes). 「黙って」 = (without a word) on one's own, silently: 黙って持ち出す (take it out without a word／on one's own). 「〜に内緒で」 = hiding from (a specific person): 親に内緒で (hiding from one's parents) — it specifically means “hiding from a specific person,” while 「こっそり／ひそかに」 don't necessarily mean hiding from anyone, just “not wanting it known, not making a fuss.” Difference: こっそり／ひそかに (neutral secretly／in secret); こそこそ (pejorative sneaking); 黙って (without a word／on one's own); に内緒で (hiding from a specific person). Test: neutrally secretly／in secret → こっそり／ひそかに; a “sneaky, guilty” pejorative → こそこそ; “without a word, on one's own” → 黙って; specifically “hiding from someone” → に内緒で. (Register: 「こっそり」 is an authentic colloquial mimetic word, natural in chat; news reporting and formal writing mostly use 「ひそかに.」)

🔄 Nuance & comparison: こっそり／ひそかに／こそこそ／に内緒で

💡 Learning tip

「こっそり・ひそかに」 both express doing something “without letting others know” — three points: ① a division of feel — 「こっそり = secretly (a concrete action, colloquial)」 (slip out／sneak a bite); 「ひそかに = in secret／inwardly (written, can be internal)」 (advance in secret／inwardly resolve); ②⭐for inner feelings (inwardly expect／respect) use ひそかに, not こっそり; ③ division of labor with 「こそこそ (pejorative sneaking)／に内緒で (hiding from a specific person).」 This set is a handy pair of adverbs for depicting “proceeding in secret” — 「こっそり」 vividly writes a concrete stealthy action, 「ひそかに」 writes a secret plan or an inner secret. To say “(concretely) secretly ～” use こっそり (colloquial), “in secret／inwardly ～” use ひそかに (written); don't write “inwardly respect” as 「こっそり尊敬.」

❓ FAQ

Q: Do 「こっそり」 and 「ひそかに」 mean the same? When do I use which?

Both express “doing something without letting others know,” but differ in emphasis and register, not always interchangeable. 「こっそり」 = secretly (a concrete stealthy action, colloquial, mimetic, neutral): it leans “a concrete, visible stealthy ‘action,'” colloquial and lively, mostly depicting physical stealthy actions: こっそり部屋を抜け出す (slip out of the room), こっそりお菓子を食べる (sneak a snack), こっそり写真を撮る (secretly take a photo), こっそりプレゼントを隠す (secretly hide a gift). It's “(physically) quietly doing some concrete action,” commonest in everyday speech. 「ひそかに」 = in secret, privately, inwardly (more written, can be internal): it leans “things advanced in secret” or “an inner secret feeling,” more written, formal: 計画がひそかに進行する (a plan proceeds in secret), ひそかに決意する (inwardly resolve), ひそかに期待を寄せる (inwardly place expectations), ひそかに恋心を抱く (inwardly harbor feelings). It can be “(a matter) proceeding in secret” or “(inwardly) quietly holding a feeling,” more written and weighty. Difference: 「こっそり」 leans a concrete stealthy action, colloquial (slip out／sneak a bite); 「ひそかに」 leans in-secret／inwardly, written (secretly plotting／inwardly expecting). Test: to say “(concretely) do some stealthy action” (colloquial, vivid) → こっそり; to say “in secret (advancing)／inwardly (a feeling)” (written) → ひそかに. Especially: inner feelings (inwardly respect／expect／yearn) always use ひそかに, not こっそり (since they aren't concrete actions). In register, 「こっそり」 is an authentic colloquial mimetic word (natural in chat, “he こっそり slipped out yesterday”), while news reporting and formal writing mostly use 「ひそかに」 (「the government ひそかに advances the plan」).

Q: What's the difference between 「こっそり」 and 「こそこそ」? Both ‘secretly'?

The difference is ‘neutral' vs ‘pejorative (sneaky, guilty).' 「こっそり」 = secretly (neutral, just not making it known, undetected): it's a neutral “secretly,” just stressing “undetected, quietly,” without the “not aboveboard” negative judgment, and can be harmless or even endearing secrecy (secretly preparing a surprise, sneaking out to play): サプライズのため、こっそり準備する (secretly prepare for a surprise — harmless, even heartwarming), こっそり抜け出す (slip out — neutral). It's just “quietly (doing something),” without criticism. 「こそこそ」 = sneakily, furtively (a negative, guilty, not-aboveboard pejorative): it carries a clear negative, pejorative flavor — stressing “(out of guilt, having something to hide) sneaking, furtive,” often with a “not aboveboard, suspicious, off-putting” judgment: 陰でこそこそ (be up to something behind the scenes), こそこそ話す (whisper furtively — with a “something's up, guilty” flavor), こそこそ逃げ回る (skulk about hiding). It's “(out of guilt) sneaking about,” with criticism. Difference: 「こっそり」 = secretly (neutral, not making it known); 「こそこそ」 = sneakily, furtively (pejorative, guilty, not aboveboard). Test: just “quietly, undetected” (neutral, can be harmless) → こっそり; a “sneaky, guilty, having-something-to-hide” negative → こそこそ. E.g. 「こっそりプレゼントを用意する (secretly prepare a gift — heartwarming, neutral)」 uses こっそり; 「何をこそこそやっているんだ (what are you sneaking about doing — a challenge, negative)」 uses こそこそ. One is a neutral “quietly,” one is a pejorative “sneakily.”

🖊️ Practice Questions (5)

Q1. 「子供たちは、親に隠れて___お菓子を食べた。」(secretly)

(A) こっそり　(B) きちんと　(C) しっかり　(D) はっきり

Q2. 「彼を___尊敬している。」(secretly, inwardly)

(A) ひそかに　(B) こっそり (for concrete actions)　(C) わざと　(D) うっかり

Q3. What does 「こっそり抜け出す」 mean?

(A) To slip out secretly

(B) To leave openly

(C) To not leave

(D) To be driven out

Q4. What is the nuance of 「ひそかに」?

(A) Secretly / privately (written; also inner, hidden feelings)

(B) Openly

(C) Loudly

(D) On purpose

Q5. Which usage is natural?

(A) ひそかに計画を進める。　(B) ひそかにを食べる。

(C) こっそりだ高い。　(D) こっそり大声で叫ぶ(矛盾)。

Answer Explanations

1. (A) こっそり ── Secretly eating snacks.

2. (A) ひそかに ── Secretly respecting (inwardly).

3. (A) ── To slip out secretly.

4. (A) ── Secretly / privately (written).

5. (A) ── 「ひそかに計画を進める」 is correct.