'answerlessly' originates from Old English and Middle English elements: the root 'answer' derives from Old English 'andswaru' (and the verb 'andswarian'), where 'and-' originally meant 'against' and 'swaru'/'swarian' related to 'a reply' or 'to swear (utter)'; the suffix '-less' comes from Old English '-lēas' meaning 'without'; the adverbial suffix '-ly' comes from Old English '-lice' meaning 'in the manner of'.

'answerlessly' changed through Middle English forms such as 'answérlesliche' / 'answerleslyche' (answer + -less + -liche/-lyche) and eventually became the modern English adverb 'answerlessly'.

Initially it conveyed the sense 'without an answer' or 'unanswered'; over time this developed into the modern adverbial sense 'in a manner that gives no answer', a meaning that has remained largely stable.