'self-chosen' originates from Modern English as a compound of 'self' + 'chosen' (the past participle of 'choose').

'chosen' comes from Old English 'gecoren' (past participle of 'ceosan'/'cēosan'), which through Middle English became 'chosen'; 'self' comes from Old English 'self'/'seolf'. These elements combined in later English to form compounds like 'self-chosen'.

Initially the components meant 'self' (oneself) and 'chosen' (selected); over time the compound retained the straightforward sense 'chosen by oneself' and its meaning has remained stable.