'jinxed' derives from the noun and verb 'jinx,' an American English word attested in the early 20th century. 'Jinx' itself is likely related to the classical name 'jynx' (Latin) / 'iunx' (Greek), a wryneck bird used in charms and folk magic.

'jinx' appeared in U.S. slang around 1911 meaning 'a charm or spell' and soon came to mean 'a person or thing that brings bad luck.' The verb sense 'to jinx' (to bring bad luck to) developed from the noun, and 'jinxed' became used as the past/past-participle and as an adjective describing something under that influence.

Initially tied to a charm or object (the bird 'jynx') used in folk magic, the word shifted to mean 'a cause of bad luck' and then the action 'to bring bad luck.' 'Jinxed' now commonly means 'affected by bad luck' or 'having been cursed/caused to be unlucky.'