I want to delete a contact from my list, but i don't want this contact to be able to see whether i am online or not. how is that possible?

 

block him first then delete him.

I only noticed this was required when I fell out with someone, and when I sorted it out an reinstated them they were still blocked and couldnt see me until I unblocked them after reinstating their name.

 

Cheers, same here.