"Yo!" (3)
'yo' is the definition.
(I know that yo can be written as hey)
This is all the clue.
(Other definitions for hey that I've seen before include "Call attracting attention" , "Exclamation calling attention" , "Exclamation to call attention" .)
(Other definitions for fro that I've seen before include "To and - means back and forth" , "Opposite direction to to" .)
'yo' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for sup that I've seen before include "Drink; take a late meal" , "Take food" , "Drink; eat evening meal" , "Imbibe" , "Drink -- eat (with the devil?)" .)