Indignant, but relaxed in measure (9)
I believe the answer is:
resentful
'indignant' is the definition.
(I've seen this before)
'relaxed in measure' is the wordplay.
I cannot quite see how this works, but
'measure' could be 'sen' (sen is a kind of measure) and 'sen' is found in the answer.
This explanation may well be incorrect...
'but' acts as a link.
Can you help me to learn more?
(Other definitions for resentful that I've seen before include "Indignant" , "Tiny wave" , "feeling sore" , "Disgruntled" , "Taking ill" .)