Definition from Wiktionary, the free dictionary
frown (plural frowns)
- A facial expression in which the eyebrows are brought together, and the forehead is wrinkled, usually indicating displeasure, sadness or worry, or less often confusion or concentration.
- (intransitive) To have a frown on one's face.
- (intransitive) To manifest displeasure or disapprobation; to look with disfavour or threateningly.
- Noisy gossip in the library is frowned upon.
- The sky doth frown and lower upon our army.
- (transitive) To repress or repel by expressing displeasure or disapproval; to rebuke with a look.
- Frown the impudent fellow into silence.
Derived terms 
to have a frown on one's face
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