To "refuse" means to say "no" to something (e.g., "I refuse to talk to him," or "I refused delivery of the item"). To "deny" means to say something isn't true (e.g., "I deny that I called him a fool"), or to not permit something (e.g., "The police denied him entry to the house").

If you deny someone, you say that they aren't connected to you at all - but this use is rather old-fashioned. To 'refuse' is the opposite of to 'accept' - if you refuse to do something you choose not to do it, or say firmly that you will not do it.

for example "he refused to deny his guilt"