To wrinkle the brows, as in frowning or displeasure; to put on a frowning look; to look sour, sullen, severe, or angry.
(by extension) To look gloomy, dark, or threatening; to lower.
To look at or repel with a scowl or a frown.
to scowl a rival into submission
To express by a scowl.
to scowl defiance
The act of giving a scowl.