To me...

Hunk is about the BODY - He is a HUNK

Stud is about the BODY And the DICK - Like a STUD Horse - You keep the stronger animals for breeding -

And the whole Frat boy thing - I would think anyone within the age range of 19 to 24 and has a slight prep look to them


I may be ALL Wrong as for proper use but these are the images I picture when I hear these words.