Deriving data from clinical, linguistic, historical, literary, and other sources, the author presents the ramifications and significances of the word 'fuck'. Some writers trace the word to the German ficken, others to the French foutre. Its close connection with the word 'suck' rests not only on the rhyme but also on a genetic and linguistic relationship. In its usage it fulfils the criteria for the postulated root words of primordial speech. The antithetical sense of primal words appears in 'suck' and 'fuck'. Here oral receptive attitudes are contrasted with oral aggressive, active phallic, and adult male sexuality. The stages and evolution of the words are described and illustrated. Other slang words for coitus also connote aggression.