Is can not one word

Answer 1

Yes spelt cannot But som lexicons do differentiate between "can not" and "cannot" "Cannot" is unequivocal: it means you do not have a choice; something you cannot do is not something you "can" or "can not" do. It means that you are not able to do that thing. You "can" or "can not" take the dog for a walk, depending on your mood. If you are confined to bed with a broken leg, however, you "cannot" take the dog for a walk, regardless of your mood.