From Longman Dictionary of Contemporary Englisheye somebody ↔ up phrasal verbLOOK AT informal to look at someone in a way that shows you think they are sexually attractive There was a group of lads at the bar, eyeing up every girl who walked in. → eye→ See Verb table
Examples from the Corpus
eye up• Suddenly a searchlight was blazing in their eyes.• When she saw me, her slightly protruding eyes lighted up.• A pair of sharp black eyes looked her up and down out of the most wasted features Miss Kyte had ever seen.• From within these, a pair of deep grey eyes looked up at him.• Six little yellow eyes peered up at him.• He lay without moving on the sand, looking out quietly from behind blue heroic eyes, up into a towering sky.• My eye picks up things in nature.• Several pairs of eyes went up to the ceiling, a few grimaces appeared. 