adj ·Moderate ·College level

Definitions

Adjective

1. 1
   Characterized by an absence of sleep: wakeful.

   "I spent a sleepless night worrying about the exams."

Adjective

1. 1
   always watchful wordnet
2. 2
   experiencing or accompanied by sleeplessness wordnet

Synonyms

All synonyms

alertwatchfulagilealiveall earsall eyes

Antonyms

All antonyms

wakeless

Example

More examples

"The affair cost me many sleepless nights."

Etymology

From Middle English slepeles, from Old English slǣplēas; equivalent to sleep + -less.

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.