coitus interruptus UK /ˈkəʊ̯.ɪtəs ˌɪntəˈrʌptəs/US /ˈkɔɪ̯.təs ˌɪntəˈrʌptəs/ noun1 •sexual intercourse interrupted by withdrawal of the penis before ejaculationThere can be no doubt, as maintained by Peyer, that the results of coitus interruptus are variable, and that very many practice it without experiencing bad results. — 1897