make a formal accusation; bring a formal charge
"The plaintiff's lawyer complained that he defendant had physically abused his client"
To express feelings of pain, dissatisfaction, or resentment.
"After waiting in line for an hour without any warning, she began to complain about the terrible service at the restaurant."
In plain English: To complain means to say that something is wrong or not good enough, usually because you are unhappy with it.
"He complained about the noise coming from his neighbor's apartment all night long."
Usage: Use complain to describe verbally expressing dissatisfaction with something specific rather than just feeling unhappy internally. Avoid using it as an intransitive verb without a target when you intend to mean that someone is simply suffering from discomfort.
The word "complain" comes from Old French and Medieval Latin origins where it originally meant to strike or beat one's chest together in grief. Over time, this physical expression of sorrow evolved into its modern sense of expressing dissatisfaction or unhappiness.