tutoies

/ty.twa/tutoyer
1.
verbInd1stPresSing2

to address someone using the informal 'tu' (to use 'tu' instead of 'vous'); to be on familiar/first-name terms

Pourquoi tu me tutoies alors qu'on ne se connaît pas ?

Why are you using 'tu' with me when we don't know each other?