Added 9 October 2026 thoughtlessly /ˈθɔt.lɪs.li/ adverb Categories: Describing WordsRare Words adverb ! Definition from Wiktionary (CC BY-SA). Pronunciation from Wiktionary, via Kaikki.org. More about thoughtlessly at Wordnik → Where our words come from → Done without thinking. He thoughtlessly invited her to come jogging, as he knew she hated exercise. Related Words: unthinkinglyunthinkingundulylightlyunthoughtedlyunreasoninglydesignlesslyunreflectinglyunknowinglyblithelyunawaresunobservingly Back to today's word