In a currish manner; in a base, cowardly, bad-tempered, or contemptible way.
From 'currish' (adjective) plus the adverb-forming suffix '-ly,' creating an adverb that describes how an action is performed in a currish manner.
This adverb is almost extinct in modern English—you'd never hear someone say 'he behaved currishly'—yet it survives in older literature as a perfect word for describing sneaky, dishonorable behavior.
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