'unshielded' originates from English, formed by the prefix 'un-' (Old English 'un-', meaning 'not') + the noun 'shield' (Old English 'scield'/'scild') with the adjectival/past-participial suffix '-ed'.

'shield' comes from Old English 'scield' (also written 'scild'), from Proto-Germanic '*skelduz' meaning 'shield'; the negative prefix 'un-' is from Old English 'un-'. These elements combined in Modern English to form 'unshield' and then 'unshielded'.

Initially it described the literal removal or absence of a physical shield ('deprived of a shield'); over time the sense broadened to general lack of protection or exposure (including figurative and technical senses, e.g., exposure to criticism or electromagnetic interference).