Seethed as muddle rose awkwardly (10)
I believe the answer is:
smouldered
'seethed' is the definition.
The answer and definition can be both related to change as well as being past participle verbs.
Perhaps they are linked in a way I don't understand?
'muddle rose awkwardly' is the wordplay.
'awkwardly' indicates an anagram.
'muddle'+'rose'='muddlerose'
'muddlerose' is an anagram of 'SMOULDERED'.
'as' is the link.
Can you help me to learn more?
(Other definitions for smouldered that I've seen before include "nearly burned" , "harboured bad emotions" , "slowly burned" .)