have a nodding acquaintance with someone or something
have a nodding acquaintance (with someone or something)
To have a slight or precursory knowledge of someone or something. Jim asked me to help fix his computer for him, but I'm afraid I only have a nodding acquaintance with how his machine works. Ruth and I had only a nodding acquaintance before going to the party, but once we got talking, it was like we'd been friends our whole lives.
have a nodding acquaintance with someone or somethingknow someone slightly; know a little about something.
1989 Donnie Radcliffe Simply Barbara Bush Their families had lived less than ten miles apart as they were growing up, and their fathers almost certainly had a nodding acquaintance on the golf course.