I mean, *a problem
Literally: two – thigh / crotch – lard / ointment – medicine
Alternately: Being here and there; refusing to commit; changing one’s position or opinion based on what seems to be favorable at the moment rather than based on principle or facts. Trying to straddle both sides of a conflict, like how an ointment applied to the inner thigh will quickly be smeared all over both legs by the act of walking.
Notes: The 膏 may also be pronounced gou with no change in meaning, and my sources don’t seem to agree on which, if either, is preferred or more common. Replacing 股 with homophone 又 (“again,” “also”) is considered an error. But a variant compound uses 内 (uchi), “inside,” in place of 二.