Soundly

Soundly is an English adverb meaning in a thorough, solid, or healthy manner. It describes actions performed with fullness or reliability, and outcomes that are robust or unambiguous. Common uses include sleeping (sleep soundly), defeating an opponent (defeat soundly), or drawing conclusions that are soundly based on the evidence.

Etymology and form: Soundly derives from the adjective sound, which in this sense means healthy, reliable, or valid. The suffix -ly turns the word into an adverb. The sense of soundly as thorough or well-founded appears in Middle English and remains common in both American and British English.

Usage and nuance: The term emphasizes thoroughness, solidity, or robust quality rather than mere quickness or superficiality. It often appears with verbs of action or with adjectives and phrases describing bases or outcomes. Examples include sleeping soundly, being soundly defeated, and conclusions that are soundly based on data. Compared with synonymous expressions, soundly tends to be more formal or emphatic about the degree of solidity or correctness.

See also: sound, soundness, unsound.