to exert, exerts, exerted, exerting, exert oneself
Mnemonic
[f-] Frodo is in the [4] bathroom of the [-(e)n] infirmary which has been converted into a 大 big田 rice field. He is wrapped in bandages from wounds he received in a recent hobbit war, and really needs to take a 大 big number two. But he can't find any stalls because they are all covered by the 田 rice field that reaches above the hobbit's little head. He 奋 exerts himself to try to find it, and he also 奋 exerts all of his energy to prevent himself from going number two before he reaches the toilet!