Train Jo to work as attendant (7)
I believe the answer is:
janitor
'attendant' is the definition.
(thesaurus)
'train jo to work' is the wordplay.
'to work' indicates anagramming the letters (letters worked into a new order).
'train'+'jo'='trainjo'
'trainjo' is an anagram of 'JANITOR'.
'as' acts as a link.
(Other definitions for janitor that I've seen before include "Caretaker (mainly US)" , "Caretaker or doorkeeper" , "(In Scotland) school caretaker" , "One employed to clean and maintain a building" , "Person looking after building" .)