1. dated To move onward or go faster. Used exclusively as an interjection, especially directed toward a horse. (In both usages, "gee" is pronounced "jee.") As the cowboys began mounting their horses, each one cried out, "Gee up!"
2. To encourage, excite, or provoke (someone) to perform at a higher level or achieve greater results. In this usage, a noun or pronoun can be used between "gee" and "up." Part of your job as a manager is geeing up your team to turn in the best results possible. If they're failing, it means you're failing. The coach tried to gee us up with an inspirational speech during halftime.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.