Compliant, acquiescent, resigned, and their corresponding nouns compliance, acquiescence, resignation, are comparable when used in reference to a person, a mood, or a disposition that manifests acceptance (as of another’s will or of something disagreeable or hard to endure).
Compliant suggests a flexibility or lack of firmness in mood or temperament and frequently implies readiness to accept meekly and without question.
Acquiescent implies acceptance without protest or rebellion; it often also connotes a temperamental lack of self-assertiveness.
Resigned usually presupposes a disposition or a temperament neither compliant nor acquiescent and implies deliberate but not necessarily happy acceptance and resolute forbearance from repining.