'off-balance' is formed in modern English by combining 'off' and 'balance'; 'off' originates from Old English 'of' meaning 'away' or 'from', and 'balance' ultimately comes from Latin and Old French meaning 'a pair of scales / equilibrium'.

'balance' came into English via Old French 'balance' (from Late Latin 'bilancia', from Latin 'bilanx' meaning 'having two pans'), and 'off' comes from Old English 'of' meaning 'away'; these elements combined in modern English to form the compound 'off-balance'.

Initially the parts meant simply 'away from balance' (a literal loss of balance); over time the compound came to be used both for physical unsteadiness and figurative senses of being unsettled or thrown off mentally.