I have notice in the list of tag synonyms that a synonym discrete-mathematics $\to$ combinatorics has been suggested. Currently it awaits votes from users.
I am not sure this is a reasonable tag synonym. But I definitely think that such a synonym should not be created without discussing it on m...
So far the reaction to the above post seems to be against the tag synonym. So I went ahead and downvoted the synonym here. (The suggested synonym is removed if it reaches score -2.)