colleagues, co-walker, fellow worker

[Ju]

1. What are the differences between colleagues, co-walker and fellow worker, please?

2. Is the above writing correct?

Ju

[emsr2d2]

1. What are the differences between colleagues, co-walker and fellow worker, please?

2. Is the above writing correct?

Ju

Firstly, it's co-worker, not co-walker.

In many cases, these three words are interchangeable. Context would probably be helpful though. It's possible that one particular word would fit a specific sentence better than any other but without any examples, it's hard to say.