this guy

A "guy" is a man. The word "guy" is informal. It sometimes carries a feeling of annoyance or dislike for a person, like in the example above. Here's another example:

I was having a conversation with Sarah, and this guy came up and said "Hi" to her.

If I was listening to a story that began this way, I would think that the speaker didn't really like the guy that she's talking about.

This phrase appears in these lessons: