In a contained manner; in a way that is controlled, restrained, or held within bounds.
From 'contained' (the adjective/past participle of 'contain') plus '-ly' (adverb suffix). This adverb describes the manner of doing something with restraint or control.
This word is mostly literary—writers use it to show character composure, describing how someone speaks or acts with emotional control, which shows how adverbs can paint psychological portraits.
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