Can I cut a cable wire?

probably best just to feed it into the hole, if possible. you may want it later. but, if you're sure you won't, then,yes, you can.

Let's hope it isn't a live electricity cable... I once witnessed a cutting of such a cable. It literally exploded and left a hole in the knife, too.
You better call some professionals to deal with the thing.

If it’s a regular old coaxial cable used for cable tv, and you are positive you won’t be needing it, AND that the service has been completely disconnected, plus it won’t violate any lease or occupancy provisions, you SHOULD be able to cut it using wire cutters.