Pronounced, "hoogaff", this is an abbreviation, or short form for "who gives a flying fuck?", something you might respond if you couldn't care less about what you just heard. It can be used in its entirety or as an adjective
When my brother told me he got a new stamp for his stamp collection I had one of those whogaff moments.
Comment: I heard there's a new reality TV show slated for the fall?