from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Slang Restless or impatient; fidgety: The long wait made the children antsy.
- adj. Slang Nervous; apprehensive: "Camps got shot up all the time, but if there wasn't a shoot-up, they'd get antsy” ( Harper's).
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. restless, apprehensive and fidgety
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adj. nervous and unable to relax
Perhaps from the incessant motions of ants.(American Heritage® Dictionary of the English Language, Fourth Edition)
From ants + -y, as in ants in one's pants. The term antsy was first noted as a rural Southern USA figure of speech in the early 20th century. (Wiktionary)