No bad temper when one is dismissed? Good! (5)
I believe the answer is:
noble
'good' is the definition.
(thesaurus)
'no bad temper when one is dismissed?' is the wordplay.
I cannot quite understand how this works, but
'no' could be 'o' (O resembles 0) and 'o' is found in the answer.
'when' could be 'e' (I've seen this in other clues) and 'e' is found in the answer.
'dismissed?' could be 'b' and 'b' is found within the answer.
This explanation may well be incorrect...
(Other definitions for noble that I've seen before include "gold coin, now obsolete" , "Having high moral character" , "Magnificent old coin" , "Blue-blooded" , "Maybe count" .)