Frenemy

Frenemy: is someone often in your professional realm or social circle that you are nice to even though you don't like them, and you are fairly certain they don't like you. You don't really have any reason not to like them other than the fact that they rub you the wrong way. They are just a little too nice, too well put together or just too well connected, but you can see through the toothy grin to the fake friendship forged out of convenience and getting ahead.

Despite your efforts, you somehow always end up at the same place though both of you happen to avoid direct contact but remain distinctly aware of each other's presence. When you bump into (slash you are cornered and have no where else to run) you have pleasant conversations through forced smiles and feigned interest appearing to be friends to onlookers, successfully hiding your true feelings. The more you attend work events and social functions, the more you realize that everyone knows your frenemy and can't stop telling you how great she is (I mean hypothetically—I am not speaking from experience, of course). This drives you crazy and reinforces her frenemy status.