こ
 
そ
 
こ
 
そ

adverb, adverb taking the と particle, takes する

Onomatopoeic or mimetic word.
  1. sneakily, secretly, stealthily, on the sly.

Variations

Pronunciation Kanji Kana Is Common
 
こ
 
そ
 
こ
 
そ
こそこそ ✔
 
コ
 
ソ
 
コ
 
ソ
コソコソ