I only have a 'nodding acquaintance' with Greek history. [=I know only a little about Greek history]
We only have a 'nodding acquaintance' with each other. [=we only know each other slightly]
“The bathroom is around the corner,” he said, 'nodding' to the left.
(..) that I didn't love. Do you remember Barry? Remember him? God, we used to make out all the time after you went to sleep. Sometimes just nodding is okay. Um, so but anyway, listen. Not marrying Barry was the best decision that I ever, ever made. Honey, Amy, you, you deserve true love (..)2003 TvShow: Friends Title: The One Where Rachel's Sister Babysits Season: 10 Episode 5