Formal:
* "I met an acquaintance from my previous job at the conference."
* "It's important to maintain a professional relationship with all business acquaintances."
Informal:
* "I ran into an old acquaintance at the coffee shop."
* "He's just a casual acquaintance, not a close friend."
* "I wouldn't say we're friends, more like acquaintances."
Descriptive:
* "The party was filled with a mix of friends and acquaintances."
* "He had a wide circle of acquaintances, but few true friends."
You can also use "acquaintance" in different contexts:
* "I'm not familiar with the city, but I have a few acquaintances who can help."
* "The author's acquaintance with the subject matter is evident in the book."
* "The meeting was a good opportunity to make new acquaintances."
The meaning of "acquaintance" depends on the context. It can refer to someone you know slightly, or to a general knowledge or familiarity with a topic.