butter wouldn't melt in someone's mouth
The identified person appears to be benign, mild-mannered, or calm (but with an integral suggestion that, to the contrary, they really are untrustworthy, disagreeable, or mean-spirited).
Meaning adapted from Wiktionary, available under CC BY-SA 4.0.
“He acts so sweet, but butter wouldn't melt in his mouth.”
“She looks innocent enough, but butter wouldn't melt in her mouth when she is trying to get her way.”
“Although he presented himself as a humble servant of the public, those who knew him best suspected that butter wouldn't melt in his mouth.”
- 01
all mouth and no trousers
Alternative form of all mouth and trousers.
- 02
all mouth and trousers
Superficial, engaging in empty, boastful talk, but not of real substance.
- 03
all one's taste is in one's mouth
One lacks good taste in aesthetic or cultural matters.
- 04
another nail in someone's coffin
An event that increases the likelihood of or causes further failure.
- 05
answer someone's prayers
To be or do exactly what someone has been wishing or asking for.
- 06
answer to someone's prayers
Exactly what someone has been wishing or asking for.
- 07
apple of someone's eye
The object of somebody's affections; a person (or sometimes a thing) that someone strongly prefers; a favorite, a loved one.
- 08
bad taste in one's mouth
A feeling that something is morally despicable as to cause nausea.
Last updated August 10, 2026