Middle English acursed, from past participle of acursen "to consign to destruction with a curse," going back to Old English acursian, from a-, perfective prefix + cursian "to curse entry 2" — more at abide

Note: The verb acursian is attested once in late Old English (glosses to the Salisbury Psalter, added in 1100 or sometime thereafter). The prefix a- may rather be a reduced form of on- than the old perfective prefix. In the 16th century spellings with initial acc- intrude, as if the word were a Romance or Latin formation with the prefix ad-.