Толковый словарь английского языка Oxford English Reference - complain

v.intr. 1 (often foll. by about, at, or that + clause) express dissatisfaction (complained at the state of the room; is always complaining). 2 (foll. by of) a announce that one is suffering from (an ailment) (complained of a headache). b state a grievance concerning (complained of the delay). 3 make a mournful sound; groan, creak under a strain. Derivatives complainer n. complainingly adv. Etymology: ME f. OF complaindre (stem complaign-) f. med.L complangere bewail (as COM-, plangere planct- lament)