'wrongfully-dismissed' is a compound formed from 'wrongfully' (from 'wrongful' + adverbial suffix '-ly') and 'dismissed' (past participle of 'dismiss'). 'Wrong' originates from Old English 'wrang' (or 'wrang') meaning 'crooked, perverse', and 'dismiss' originates from Latin 'dimittere' where the prefix 'di-/dis-' meant 'away' and 'mittere' meant 'to send'.

'wrong' developed from Old English 'wrang' through Middle English into modern English 'wrong'; 'wrongful' was formed by adding the suffix '-ful' to mean 'full of wrong/ unjust', then '-ly' produced 'wrongfully'. 'Dismiss' came from Latin 'dimittere' → Old French/Medieval Latin forms → Middle English 'dismiss(en)' and then modern English 'dismiss', with the past participle becoming 'dismissed'. The compound adjectival phrase 'wrongfully dismissed' arose from combining the adverbial modifier with the past participle in legal and everyday usage.

Initially, 'wrong' had senses like 'crooked' or 'perverse' and 'dimittere' meant 'to send away'; over time 'wrong' shifted to mean 'not correct' or 'unjust', and 'dismiss' developed a common sense 'to remove from a job or position'. Together the compound now specifically conveys 'removed from a job unjustly or unlawfully.'