out of place

“Rebuke:Scold” is a pair of word which is out of place.

What is the meaning of the bold part?

“out of place” is a set expression meaning “not in the correct place” or “not fitting properly”.

It should read “is a pair of words”.

Then
How is “Rebuke:Scold” a pair of words which is out of place?

That is grammatically possible, but it feels a bit laboured, and I suspect it would normally be said in a different way. What is the context?