on a first-name basis

on a first-name basis

So familiar or friendly with someone as to be comfortable referring to them by their first name (as opposed to being more formal and using their surname). Don't worry, we'll get in—I'm on a first-name basis with the owner of the club. Wow, since when are you on a first-name basis with a famous author?
See also: basis, on

*on a first-name basis (with someone)

knowing someone very well; good friends with someone. (*Typically: be ~; get ~.) I'm on a first-name basis with John. John and I are on a first-name basis.
See also: basis, on

on a first-name basis

Quite familiar and friendly, as in Practically all the guests were on a first-name basis. This idiom alludes to the fact that using a person's given name betokens familiarity. [Second half of 1900s]
See also: basis, on