unbalanced (adj.)youdaoicibaDictYouDict
1640s, from un- (1) "not" + past participle of balance (v.). Earliest use is in reference to the mind, judgment, etc. Of material things, it is recorded from 1732.
well-balanced (adj.)youdaoicibaDictYouDict
1620s, from well (adv.) + past participle of balance (v.).