Not if I see you sooner, and Not if I see you first.

Inf. a response to I'll see you later. (This means you will not see me if I see you first, because I will avoid you.) Tom: See you later. Mary: Not if I see you sooner. John: Okay. If you want to argue, I'll just leave. See you later. Mary: Not if I see you first.

McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.