Bad-tempered Greek that hurt you early on (7)
I believe the answer is:
grouchy
'bad-tempered' is the definition.
('grouchy' can be a synonym of 'bad-tempered')
'greek that hurt you early on' is the wordplay.
'greek' becomes 'gr'.
'that hurt' becomes 'ouch' (I've seen this before).
'you early' becomes 'y' (I can't justify this - if you can you should give a lot more credence to this answer).
'on' means one lot of letters go next to another.
'gr'+'ouch'+'y'='GROUCHY'
(Other definitions for grouchy that I've seen before include "Querulous" , "ill-tempered" , "Bad-tempered" , "Given to grumbling" , "Grumpy" .)