Cross empty gallery to take seat (6)
I believe the answer is:
grumpy
'cross' is the definition.
('grumpy' can be a synonym of 'cross')
'empty gallery to take seat' is the wordplay.
'empty' says to hollow out the word (remove centre letters).
'to take' means one lot of letters goes inside another.
'seat' becomes 'rump' ('rump' can be a synonym of 'seat'**).
'gallery' with its middle taken out is 'gy'.
'gy' placed around 'rump' is 'GRUMPY'.
(Other definitions for grumpy that I've seen before include "short one" , "Ill-humoured" , "Surly, ill-tempered" , "An ill-tempered dwarf of group of Seven" , "Gloomy and irritable like sour old man" .)