Not really, an opposite word to complain would be BE GRATEFUL or COMPLEMENT
Agreement
agreement
opposite of fifight is
Words that are opposites (antonyms) of disharmony are agreement, peace, accord, and harmony.
the opposite of "arguement" is "agreement"
A more form word for complaint is grievance.
Agreement.
The opposite of dispute is agreement or consensus.
The opposite of a compliment (praise) would be a criticism, complaint, or rebuke. The opposite of the verb could be to complain, criticize, or insult.
Agreement
1. lack of consensus or approval 2. lack of consistency or correspondence
The word 'complaint' is an abstractnoun; a word for an expression of discontent, regret, pain, censure, or resentment; a word for a concept.