こっそり

adverb

secretly; stealthily; quietly

1. secretly; stealthily; on the sly

Describes doing something quietly and secretly so as not to be noticed by others. Often implies a deliberate attempt to avoid detection.

こっそり部屋(へや)を出(で)た。

I slipped out of the room quietly.

彼(かれ)はこっそり手紙(てがみ)を読(よ)んでいた。

He was reading the letter secretly.

親(おや)に見(み)つからないようにこっそりお菓子(かし)を食(た)べた。

I ate snacks on the sly so my parents wouldn't find out.

こっそり describes doing something secretly or stealthily, deliberately trying not to be noticed. The tone is relatively mild — it can describe innocent secrecy, not just wrongdoing.

Common patterns

こっそり〜する: to do something secretly
こっそりと: variant with と particle (slightly more literary)
こっそり抜(ぬ)け出(だ)す: to sneak out
こっそり食(た)べる: to eat on the sly

Similar words

こそこそ: sneakily (more negative, implies suspicious behavior)
ひそかに: secretly (literary, can mean "inwardly")
内緒(ないしょ)で: in secret, confidentially
密(ひそ)かに: in secret (formal/written)

Usage

こっそり often appears in lighthearted contexts: こっそりお菓子(かし)を食(た)べる (sneaking a snack). こそこそ sounds more suspicious and negative.

Related Words

Compare: こそこそ (sneakily (negative))

Compare: ひっそり (quietly, unobtrusively)

Compare: 密(ひそ)かに (secretly)

Related: 人目(ひとめ)を忍(しの)ぶ (to avoid being seen)

Compare: 陰(かげ)で (behind someone's back)

general

Added 2026.1.16 23:51 · Revised 2026.9.2 13:01

05500/05890_kossori