Guapo in spanish means handsome. When applied in this sense it is used as a paradox to that definition however. Guapo is usually used by a group of friends as a nickname to the kid in the group who is the fattest and ugliest as a put down. It is basically a form of sarcasm.
"Hey, are you gonna go to that party guys!? If you do, can i come too?"
"Shut the fuck up El Guapo"
A fine type of peach-fuzz that grows on a man or womans face that covers the upperlip on eather side of the nose and on the chin, it is very handsome. A guapo isnt quite a mustache although the owners seem to think so.
look at that girl, why doesnt she shave that guapo