Kenneth G. Wilson (1923–). The Columbia Guide to Standard American English. 1993.
plaintiff (n.), complaint (n.), plaintive (adj.)
The prefix plaint- is cognate with complaint, and all these plaint- words stem ultimately from planctus, a Latin past participle meaning “to lament,” but complaint itself has two main meanings: “legal complaint (the bringing of a suit in a court of law)” and “grief and dissatisfaction.” In the latter cluster is the malady or illness sense: One symptom of this complaint was a racking cough. The noun plaintiff is the name given the person bringing a complaint in a legal matter. The adjective plaintive means “mournful, sad, melancholy, or woeful.”
