'unclasp' originates from Middle English, specifically the prefix 'un-' meaning 'reverse action' and the word 'clasp' meaning 'to fasten or hold tightly'.

'unclasp' changed from the Middle English word 'unclaspien' and eventually became the modern English word 'unclasp'.

Initially, it meant 'to open or release a clasp', and this meaning has largely remained the same in modern usage.