An Etymological Dictionary of Astronomy and Astrophysics

An expression of discontent, regret, pain, censure, resentment, or grief; lament; faultfinding (Dictionary.com).

Etymology (EN): M.E. compleynte, from O.Fr. complainte “complaint, lament,” noun from complaindre “to lament,” → complain.

Etymology (PE): Verbal noun of garzidan, → complain.