ばてる
ばてる · bateru · JLPT N1 · verb-ichidan
to be exhausted
Sounds like bat plus tired: bateru means worn out after a long, hard day, like a bat drained by a night of effort.
Colloquial verb for fatigue from heat, sport or hard work, stronger and more casual than 疲れた (tsukareta). Use it when you have run out of energy in the middle of an activity.