The word 'unknot' is a transparent English formation built from the native Germanic base 'knot' and the reversative prefix 'un-'. The Old English noun cnotta is related to other Germanic words like Middle Low German knotte and Old Norse knútr, all pointing to the concept of a tied fastening. The prefix 'un-', used to form verbs expressing reversal, has been productive in English since its earliest stages. Therefore, 'unknot' follows a straightforward and logical morphological pattern, literally meaning "to reverse the state of being knotted," which directly aligns with its modern definition of untying a knot.

Structure: un (reverse action) + knot (a fastening made by tying a piece of rope, string, etc.) - un: A prefix of Germanic origin (Old English un-, on-) meaning "to reverse, remove, or deprive of." It functions as a reversative or privative prefix. - knot: A noun of Germanic origin (Old English cnotta), referring to a fastening made by looping and tying a cord or rope. It functions as the base word specifying the object of the action.