'unforeseeably-released' originates from the combination of 'unforeseeably' and 'released'. 'Unforeseeably' is derived from 'un-' meaning 'not', 'foresee' meaning 'to see beforehand', and '-ably' indicating manner. 'Released' comes from the Old French 'reles', meaning 'to let go'.

'Unforeseeably' evolved from the Middle English 'unforseen', while 'released' transformed from the Old French 'reles' to the modern English 'release'.

Initially, 'unforeseeably' meant 'in a manner not seen beforehand', and 'released' meant 'to let go'. The combined term retains these meanings in modern usage.