frown

American Heritage® Dictionary of the English Language, Fourth Edition

1. v. To wrinkle the brow, as in thought or displeasure.
2. v. To regard something with disapproval or distaste: frowned on the use of so much salt in the food.
3. v. To express (disapproval, for example) by wrinkling the brow.
4. n. A wrinkling of the brow in thought or displeasure; a scowl.

Century Dictionary and Cyclopedia

1. To contract the brow as an expression of displeasure or severity, or merely of perplexity, concentrated attention, etc.; put on a stern or surly look; scowl.
2. To look or act disapprovingly or threateningly; lower: as, to frown upon a scheme.
3. To repress or repel by an aspect of displeasure; rebuke by a stern or angry look or by severe words or conduct: as, to frown one into silence; to frown down a proposition.
4. n. A contraction or wrinkling of the brow expressing displeasure or severity, or merely perplexity, difficult concentration of thought, etc.; a severe or stern look; a scowl.
5. n. Any expression or show of disapproval or displeasure: as, the frowns of Providence.

Wiktionary

1. n. 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.
2. v. intransitive To have a frown on one's face.

GNU Webster's 1913

1. v. To contract the brow in displeasure, severity, or sternness; to scowl; to put on a stern, grim, or surly look.
2. v. To manifest displeasure or disapprobation; to look with disfavor or threateningly; to lower.
3. v. To repress or repel by expressing displeasure or disapproval; to rebuke with a look.
4. n. A wrinkling of the face in displeasure, rebuke, etc.; a sour, severe, or stern look; a scowl.
5. n. Any expression of displeasure

WordNet 3.0

1. n. a facial expression of dislike or displeasure
2. v. look angry or sullen, wrinkle one's forehead, as if to signal disapproval