ˌoff-ˈbalance BrE AmE , off balance adjective [not before noun]
1 . in an unsteady position and likely to fall
throw/knock/push etc somebody off-balance
The sudden movement of the ship knocked them both off balance.
2 . catch/throw somebody off-balance to surprise or shock someone because they are not prepared for something that happens:
I was thrown off-balance by some of the more difficult questions I was asked.