The compound adjective 'well-adjusted' is a modern psychological term built from native English elements. The adverb 'well', with ancient Germanic roots meaning "in a good way," intensifies the past participle of 'adjust', a verb borrowed from French that carries the Latin sense of bringing something close to a correct standard. The '-ed' suffix completes the form, creating a descriptive adjective. Thus, the literal "having been adapted well" evolved into the specialized modern meaning describing a person who has successfully adapted their psyche and behavior to the demands of their environment, achieving a state of balanced mental and social health.

Structure: well (in a good manner) + adjust (to adapt) + ed (adjective suffix) - well: From Old English wel, meaning "in a good manner, rightly, properly." It functions as an intensifying adverb modifying the participle. - adjust: From Old French ajuster, meaning "to arrange, adapt." It is the core verb root, derived ultimately from Latin ad- (to) + iuxtare (to come near). In this compound, it is used in its past participle form. - ed: A suffix from Old English -ed, -od, -ad, used to form adjectives from verbs, indicating a state or condition resulting from the action of the verb.