Formal:
* "The fellow who spoke at the conference was very insightful."
* "My fellow students and I are all working hard for the upcoming exams."
* "The company is looking for a fellow with experience in marketing."
Informal:
* "Hey fellow coffee lovers, let's grab a cup!"
* "That fellow over there seems to be lost."
* "I'm not sure what that fellow is up to, but he looks suspicious."
Other uses:
* "He was a fellow traveler on the train."
* "The two fellows agreed to meet for lunch."
* "The fellow's name is John."
Remember, "fellow" can be used to refer to a person, often in a friendly or informal way. It can also be used more formally, especially in academic or professional settings.