Some yob arrives in pub (3)
I believe the answer is:
bar
'pub' is the definition.
(both are drinking establishments)
'some yob arrives in' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'BAR' can be found hidden inside 'yob arrives in'.
(Other definitions for bar that I've seen before include "Hostelry" , "Prevent; pub" , "Pole" , "Except; counter" , "Length of wood or metal - drinking place" .)