Supporters for empty pits (5)
I believe the answer is:
props
'supporters' is the definition.
(things that prop up or support)
'for empty pits' is the wordplay.
'for' becomes 'pro' (as in being 'pro' something).
'empty' means to remove the middle letters.
'pits' with its middle removed is 'ps'.
'pro'+'ps'='PROPS'
(Other definitions for props that I've seen before include "Items used on stage" , "Buttresses" , "forwards" , "Set" , "Forward types" .)