'half-hidden' originates from Old English components: 'half' (from Old English 'healf'), and 'hidden', the past participle form of 'hide' (from Old English 'hȳdan'), where 'healf' meant 'half' and 'hȳdan' meant 'to hide.'

'half-hidden' developed in Middle English as compound forms such as 'half-hid' or 'half-hiden' and eventually became the modern English compound adjective 'half-hidden.'

Initially it meant literally 'half in a hidden state' (partly concealed), and this basic sense has largely remained the same in modern usage.