• (n.) A term or word which is the opposite of, or antithesis to, another; an antonym; -- the opposite of synonym; as, `foe` is the counterterm of `friend`.
Coun'ter·term` noun A term or word which is the opposite of, or antithesis to, another; an antonym; -- the opposite of synonym ; as, 'foe' is the counterterm of 'friend'. C. J. Smith.