Having a wide variety of effects, not able to do a single desired thing in isolation. Often used about drugs
Yeah, I could take doxylamine to get to sleep, but anticholinergics also cause dry mouth and difficulty urinating. That's a pretty bad trip.
or weapons
So what if we have a two-megadeath nuclear device? This is a war of conquest! It's not particularly useful to kill your enemies if the air is poisoned and the ground's been turned to glass.
When used in medicine, this is not a seriously
pejorative term. It seems to evoke "dirty" in the sense of
messy, rather than "dirty" in the sense of
soiled or
immoral.