in an irritable, quarrelsome, or bad-tempered manner; expressing or showing peevish irritation.
From fractious (adjective) + -ly (adverb suffix). Fractious comes from Latin fractus (broken, irritable) and suggests a 'broken' or disrupted state of temper.
Fractious and fraction share the same Latin root fractus (broken), but fractious means a broken temperament while fraction means a broken quantity—etymology reveals two types of breaking.
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