1 to express resentment, displeasure, etc., esp. habitually; grumble
2 foll by: of to state the presence of pain, illness, etc., esp. in the hope of sympathy
she complained of a headache
(C14: from Old French complaindre, from Vulgar Latin complangere (unattested), from Latin com- (intensive) + plangere to bewail)
♦
complainer n
♦
complainingly adv