'unpeeled' is formed from the prefix 'un-' (Old English 'un-', meaning 'not') combined with the verb 'peel'. The verb 'peel' comes via Middle English from Old French 'peler' meaning 'to strip the skin or bark off', ultimately related to Latin roots meaning 'to pull off'.

The element 'peel' changed from Old French 'peler' to Middle English forms such as 'pelen' and later became modern English 'peel'; the negative prefix 'un-' (Old English) was attached in English to form 'unpeel' and its past/past-participle 'unpeeled'.

Initially the root meant 'to strip skin or bark off', and over time 'unpeel/unpeeled' retained the literal sense of removing or not having removed an outer covering; in modern usage 'unpeeled' commonly denotes 'not peeled' and may also be used descriptively.