Added 9 October 2026 labourious adjective Categories: Obscure Words adjective ! Definition from Wiktionary (CC BY-SA). More about labourious at Wordnik → Where our words come from → Obsolete form of laborious. Related Words: toilsomelaboriousbackbreakingarduousgruellingpunishingeffortfulhardgruelingheavycumbersomestrenuous Back to today's word