Refusing to change (7)
I believe the answer is:
adamant
'refusing to change' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for adamant that I've seen before include "Unyielding to requests, stubborn" , "Firm and unyielding" , "Inflexible: fabulously hard rock" , "Inflexible, obdurate" , "popstar" .)