Stand, seeing everybody by empty seat (5)
I believe the answer is:
stall
'stand' is the definition.
('stall' can be a synonym of 'stand')
'everybody by empty seat' is the wordplay.
'everybody' becomes 'all' (I've seen this before).
'by' means one lot of letters go next to another.
'empty' means to remove the middle letters.
'seat' with its middle removed is 'st'.
'all' put after 'st' is 'STALL'.
'seeing' acts as a link.
(Other definitions for stall that I've seen before include "Come to a halt" , "Put off" , "Enclosure" , "Play for time" , "Canon's seat" .)