Unbalanced is from un- ('not') + balanced, from balance, from Old French balance, from Late Latin bilancia, from Latin bilanx ('having two scale-pans'), from bi- ('two') + lanx ('plate, scale'). Important recorded forms include un- (Old English), bilanx (Latin), and lanx (Latin). Morphologically, the un- element marks negation, reversal, removal, or deprivation, while the base supplies the action, quality, or state being denied or undone. The modern sense is largely compositional, with the historical elements narrowing into a stable English lexical item. In current use it covers not in equilibrium; or mentally disturbed. The wider family includes related words such as balance, balanced, and imbalance.