Added 10 October 2026 sleepiness noun Categories: Describing WordsRare Words In Latin: veternus Wiktionary noun ! Definition from WordNet 3.1, Princeton University. More about sleepiness at Wordnik → Where our words come from → A very sleepy state. sleepiness causes many driving accidents Related Words: somnolencedrowsinesssleeplessnessinsomniasedationsleepfulnessunsleepinesssnoozinesssleepnesssomniferousnessslumberousnesssleeping Back to today's word