Refusing to yield meant trouble in the sky (9)
I believe the answer is:
firmament
'the sky' is the definition.
(I've seen this before)
'refusing to yield meant trouble' is the wordplay.
I cannot quite see how this works, but
an anagram of 'meant' is 'ament' which is present in the answer.
The remaining letters 'firm' is a valid word which might be clued in a way I don't see.
This may be the basis of clue (or it may be nonsense).
'in' is the link.
Can you help me to learn more?
(Other definitions for firmament that I've seen before include "The starry heaven" , "Heavens, sky" , "The celestial sphere" , "Sky (literary)" , "outer space, encapsulated" .)