addict, nut, freak, junkie, junky -- (someone who is so ardently devoted to something that it resembles an addiction; "a golf addict"; "a car nut"; "a bodybuilding freak"; "a news junkie")
testis, testicle, orchis, ball, ballock, bollock, nut, egg -- (one of the two male reproductive glands that produce spermatozoa and secrete androgens; "she kicked him in the balls and got away")