squirrely

[skwur-uh-lee, skwuhr- or, esp. British, skwir-]

adjective Slang.

Origin of squirrely

First recorded in 1930–35; squirrel + -y¹

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

I guess I did because I was—they told me I was squirrelly in the hospital.
Warren Commission (11 of 26): Hearings Vol. XI (of 15)
The President's Commission on the Assassination of President Kennedy

1925, from squirrel (n.) + -y (2). Related: Squirreliness.