A term a lot of British people use in place almost any and every noun, often to sound hip or smart. A lot of the time it is used because they could not think of another noun to use or do not want be so offensive as to swear in some way.
"Yeah, I was walking home from school when four chaps beat the guff out of me."
" I saw him too, what a guff."
"I was talking to Brad at work, when he asked me if I wanted some of this guff he was eating; I was like, hell no.""
"I came home and dad was pulling this guff from the drain, pretty rank stuff."
"Yeah, she looked like guff yesterday."
Randomer 1 "I put his guff in my guff and it felt like guff from Jack."
Randomer 2 " You sound like a gay guff."
Randomer 1 " How is liking guff gay?"