expression, godan verb (-u)
feign innocence; play dumb
Idiomatic expression literally meaning 'wipe one's mouth'; used when someone pretends not to know about something they were involved in, like a child sneaking food and wiping their mouth to hide the evidence.
彼は知っているくせに、口を拭うように「何も知らない」と言った。
Even though he knew, he said 'I don't know anything' as if feigning innocence.
expression, godan verb (-u)
wipe one's mouth
Literal meaning of the phrase; simply wiping one's mouth after eating or drinking.
食事の後、ナプキンで口を拭った。
After the meal, I wiped my mouth with a napkin.