adjective, ants·i·er, ants·i·est. Informal.
- unable to sit or stand still; fidgety: The children were bored and antsy.
- apprehensive, uneasy, or nervous: I’m a little antsy since hearing those storm warnings.
adjective antsier or antsiest
- informal restless, nervous, and impatient
1838, American English, from plural of have ants in (one’s) pants “be restless and fidgety” from a century later. Related: Antsiness.+ (2); probably reflecting the same image as the slang expression