The relationships of various aspects of idiomatic communication to the interpersonal sentiments of 100 romantically involved heterosexual couples were examined. After completing measures of loue, liking, commitment, and closeness, the partners of each dyad were questioned about any words, phrases, or nonverbal signs they had created that had meaning unique to their relationship.The 647 idioms reported were codedfor theirform (i.e., verbal versus nonverbal), context of use (i.e., private idioms, which were usedonly when others were not present, versuspublic idioms, which could be usedin the presence ofothers), and function (i.e., confrontations, expressions of affection, labels for outsiders, nicknames, requests, sexual invitations, sexual references/euphemisms, and teasing insults). For both sexes, loving, commitment, and closeness were correlated with number of reported idioms that expressed affection, initiated sexualencounters, and referred to sexualmatters. Theonly significant relationship for liking was between females' liking scores and the frequency of idioms with sexual referents. A log-linear analysis revealed a significant association between the function of the idioms and their form; labelsfor outsiders, nicknames. sexual references/euphemisms, and teasing insults were almost always verbal. A significant association was alsofound between idiomfunction andcontext of use; labelsfor outsidersand teasing insults were most often usedin situations inuolving other people, whereas sexual invitations and sexual referencesleuphemisms were usually used in private situations. Finally, males were the inventors of idioms much more often than females.OCIAL observers from several disciplines have noted that people in close contact often develop idiosyncratic ways of S