tutoyer

[ too-twah-yey; French ty-twa-yey ]
/ ˌtu twɑˈyeɪ; French tü twaˈyeɪ /

verb (used with object), tu·toy·ered or tu·toy·ed [too-twah-yeyd] /ˌtu twɑˈyeɪd/, tu·toy·er·ing [too-twah-yey-ing] /ˌtu twɑˈyeɪ ɪŋ/.

to address (someone), especially in French, using the familiar forms of the pronoun “you” rather than the more formal forms; address familiarly.

Origin of tutoyer

1690–1700; < French, to address as tu and toi (the familiar singular forms for “you” in French)