(adj. and adv.) Not right, not correct, impolite, rude, improper, treyf, crazy; not ready, not alert; in baseball and softball, not touching one of the bases and thus vulnerable to being tagged out.
"I don't like Hillary either, but his remarks about her were way off base."
"Joe was off base so he was easily tagged out."
1. not appropriate
2. by surprise
3. incorrect, not accurate
His claims are totally off base.