Knowing what a word means is critical to using it correctly. If you use the expression "work colleagues", what you're really saying is that that you don't know what "colleagues" means.
Picture: Getty Images/Steve Eason/Hulton Archive
Here's the definition of colleagues from the Macquarie Dictionary:
an associate in office, professional work etc.
More simply, colleague means "someone you work with". So you don't need to add "work" to the front -- there is no such thing as a non-work colleague.
You wouldn't write "female woman" or "family relative" or "canine dog", so don't write "work colleague" either. Accuracy matters.
Lifehacker's Mind Your Language column offers bossy advice on improving your writing.