Keep down on hold (7)
I believe the answer is:
repress
This clue is a double definition.
'keep down' is the first definition.
(I know that keep down can be written as repress)
'hold' is the second definition.
(thesaurus)
'on' acts as a link.
(Other definitions for repress that I've seen before include "Check" , "Forcibly keep down" , "Put in irons, maybe" , "Curb" , "Silence" .)