• If a defendant fails to assert a compulsory counterclaim in the original action, that claim may not be brought in a later, separate action (with some excep-tions). See Fed. R. Civ. P. 13(a). [Cases: Federal Civil Procedure 775; Judgment 585(4); Set-off and Counterclaim 60. C.J.S. Judgments §§ 775, 777–778; Set-off and Counterclaim §§ 102–103.]
compulsory counterclaim
A counterclaim that must be asserted to be cognizable, usu. because it relates to the opposing party’s claim and arises out of the same subject matter.