Weakened anew, perhaps, to a bad end (5)
I believe the answer is:
waned
'weakened' is the definition.
The answer and definition can be both related to change as well as being past participle verbs.
Maybe they are linked in a way I don't understand?
'anew perhaps to a bad end' is the wordplay.
'perhaps' is an anagram indicator.
'to' says to put letters next to each other.
'end' indicates one should take the final letters.
The last letter of 'bad' is 'd'.
'anew' with letters rearranged gives 'wane'.
'wane'+'d'='WANED'
Can you help me to learn more?
(Other definitions for waned that I've seen before include "(Of moon) grew smaller" , "Decreased in size" , "grew faint" , "Ebbed; declined" .)