General Synonyms:
* Tired
* Weary
* Fatigued
* Drained
* Spent
* Worn out
* Burned out
* Depleted
* Used up
* Beat
* Knocked out
* Bushed
* Done in
More Formal Synonyms:
* Enervated
* Debilitated
* Prostrated
* Languid
* Listless
Words Conveying Specific Causes:
* Exhausted from work: Overworked, Stressed, Burned out
* Exhausted from travel: Jet-lagged, Travel-weary
* Exhausted from illness: Debilitated, Prostrated, Weak
* Exhausted from emotional stress: Overwhelmed, Burned out, Drained
Informal Synonyms:
* Dead tired
* Totally wiped
* Done for
* Ready to drop
* Ready to sleep
The best synonym for "exhausted" depends on the context and the specific nuance you want to convey.