To unite in a league or alliance; join in a mutual contract or covenant.To cause to unite in a league; ally.United in a league; allied by compact or treaty; engaged in a confederacy; leagued; pertaining to a confederacy.Specifically [capitalized] Pertaining to the Confederate States of America: as, the Confederate government or army.n. One who is united or banded with another or others in a compact or league; a person or nation engaged in a confederacy; an ally; an associate; an accomplice.n. Specifically A citizen or subject of one of a number of confederated states; specifically (with a capital), a citizen or soldier of any one of the southern States of the American Union which formed the Confederate States of America, who participated in or sympathized with the attempt to destroy the Union by secession and the prosecution of the civil war.n. Synonyms Friend, Companion, etc. (see associate), accomplice, accessory, abetter, fellow-conspirator.