Restless or short-tempered (9)
I believe the answer is:
impatient
This clue is a double definition.
'restless' is the first definition.
(similar in meaning)
'short-tempered' is the second definition.
(thesaurus)
(Other definitions for impatient that I've seen before include "Over-eager" , "those who hate waiting" , "dying" , "appeared anxious" , "Unlike Job" .)