breakup (n.) Look up breakup at Dictionary.com
also break-up, 1795, from verbal expression break up (mid-15c.), which was used originally of plowland, later of groups, assemblies, etc. Of things (also of marriages, relationships), "to disintegrate," from mid-18c. See break (v.) + up (adv.). Break it up as a command to stop a fight, etc., is recorded from 1936.