What is "dogooder"

Usage examples of "dogooder".

Mostly because you are not an effete trainee new to the job, or a dogooder officer of the law.

Then the dogooders got hold of him and primed him to spill before the state committee investigating boxing, and the gangsters kidnaped him one night and cut his tongue out.

Psychopathic dogooders, always sticking in their noses, never letting well enough alone.