give someone the eye
give someone the eyeINFORMAL
If you give someone the eye, you look at them in a way that shows that you find them attractive. They've been giving each other the eye all the time they've been in the queue.
give someone the (glad) eyelook at someone in a way that clearly indicates your sexual interest in them. informal
1992 James Meek Last Orders If it was an attractive woman, men would give her the eye.