Meaning of “complain of sth” - Learner’s Dictionary

complain of sth

phrasal verb with complain uk us /kəmˈpleɪn/ verb [ I ]

B1 to tell other people that something is making you feel ill:

She's been complaining of a headache all day.

(Definition of “complain of sth” from the Cambridge Learner’s Dictionary © Cambridge University Press)