Composer dismissing a writer and painter (2,5)
I believe the answer is:
el greco
'painter' is the definition.
(I've seen this before)
'composer dismissing a writer' is the wordplay.
'composer' becomes 'elgar' (Edward Elgar).
'dismissing' suggests deleting specific letters.
'writer' becomes 'eco' (I've seen this before).
'elgar' with 'a' removed is 'elgr'.
'elgr'+'eco'='EL GRECO'
'and' acts as a link.
(Other definitions for el greco that I've seen before include "Spanish painter, nicknamed for his place of birth" , "Spanish painter born in Greece" , "Domenikos Theotokopoulos" , "Greek born Spanish painter" , "Famous painter's nickname" .)