In a manner that answers or responds to something; in a way that serves as an answer or corresponds to a question.
From answering (the present participle of answer) plus the adverb suffix -ly, creating an adverb from a verb form rather than an adjective.
This adverb is quite archaic and poetic—you'd find it in older literature where authors wanted to describe how something 'answered' or corresponded to something else in an almost musical or metaphorical way!
Complete word intelligence in one call. Free tier — 50 lookups/day.