To notice and/or show a particular interest in something - usually a hot guy/girl, but can also be a meal or anything really.
Dan, check that girl out by the bar, she is totally eyeing you up dude.

Tom's order took so long to get, I caught the fat bastard eyeing up my Big Mac a few times.
by Synapse000000000666 May 31, 2007
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to look at someone in a way that shows you are sexually attracted to them
I always eye up hot girls
by Erick Freeze December 28, 2013
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what a friend/girl tells you when your looking at a girls ass or tits instead of your friend or her eyes
Ruben- Eyes up John
John- dude i cant help it
by akdieloe September 12, 2010
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A friendly greeting, often used in the West Midlands and North of England.
Used in typical conversation:

Emma: "Ey up duck, ows yer ma?" (Hello, how is your mother?)
Lee: "Shes alreet" (She is doing well)
by JB40k April 03, 2008
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Keeping an eye open. Watching out. Being aware.
And "trust" is a word you seldom hear from us
Hustlers we don't sleep we rest one eye up

-Jay Z, "December 4th"
by mjsgdjkabskjfbj May 07, 2009
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