Middle English, from Latin callosus, from callum, callus callous skin First Known Use Adjective 14th century, in the meaning defined at sense 1a Verb 1769, in the meaning defined above Time Traveler The first known use of callous was in the 14th century See more words from the same centu...
Definition of callously adverb in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.