queixar

In a sentence

• Em queixaré si no em donen el que em van prometre.

  I will complain if they do not give me what they promised.

  Here, 'queixar-se' means 'to complain,' used reflexively, indicating a subject expressing dissatisfaction.

• Els teus veïns han vingut a queixar-se del soroll de la festa.

  Your neighbors came to complain about the noise from the party.

  'Queixar-se' is used reflexively in the past action indicating someone expressing an issue to others.

• Per què et queixes tant, si tot està bé?

  Why do you complain so much if everything is fine?

  'Queixar-se' here is used reflexively in a question to question someone's expression of discontent without apparent reason.