Also found in: Dictionary.
To brush hair to the back of the head and cause it to lie flat with water, oil, gel, or some other product. A noun or pronoun can be used between "slick" and "back." I wanted to slick my hair back for our school photos, but Mom wouldn't let me. Try slicking it back first, then style it from there.
To cause something, especially hair, to lie flat by making it moist or oily and brushing it back: He wet his hands and slicked back his hair. She slicks her curls back with gel.