When a chick looks good from far away or at a glance, but then the sad reality becomes clear that they are as ugly as the north-bound end of a south-bound horse when approached or when a better view is available. Also, cute in theory
Dude: Bro, did you get a good look at that hottie that just passed us? I missed her.
Bro: Yeah dude, don't worry about it, shes only theoretically cute, nothin to worry about.
Bro: Holy crap dude, you didn't tell me you had a sexy-ass neighbour!
Dude: Yeah cus she's just cute in theory