On overhead (5)
I believe the answer is:
above
I believe this clue is a double definition.
'on' is the first definition.
(thesaurus)
'overhead' is the second definition.
(thesaurus)
(Other definitions for above that I've seen before include "Aforementioned" , "Given earlier (in text)" , "Too good for" , "Overhead" , "At a higher level" .)