To spend time or hang out with someone, especially at a social event.
To hobnob is to spend time or hang out with someone, especially at a social event. When you’re invited to a fancy benefit party at a museum, you might get to hobnob with socialites and minor celebrities.
When you hobnob, you mingle or pal around with fancy folks. People who work in book publishing occasionally get to hobnob with writers, and if you get a job on a movie set, you may have a chance to hobnob with movie stars. Hobnob first meant “to drink to one another,” or “to toast each other.” In Britain, a HobNob is also a popular cookie or biscuit brand.
Thanks to Vocabulary.com