'unkinked' originates from English, specifically formed from the prefix 'un-' + the noun/verb 'kink', where 'un-' meant 'not' and 'kink' meant 'a twist, bend, or sharp fold'.

'kink' is recorded in late Middle English (e.g. 'kinke') meaning 'a bend or twist', likely from or influenced by northern/Scandinavian dialects; the verb 'unkink' (to remove a kink) is a later formation by adding the negative/prefix 'un-' to 'kink', producing past/p.p. 'unkinked'.

Initially the elements conveyed 'not' + 'twist/bend'; over time the compound came to be used specifically for the action/result of removing a kink, now meaning 'freed from kinks' or 'straightened'.