Introduced a safety device amid chaotic din (7)
I believe the answer is:
infused
'introduced a safety' is the definition.
The answer and definition can be both related to change as well as being past participle verbs.
Maybe you can see a link between them that I don't see?
'device amid chaotic din' is the wordplay.
'device' becomes 'fuse' (fuse is a kind of device).
'amid' is an insertion indicator.
'chaotic' indicates an anagram.
'din' with letters rearranged gives 'ind'.
'fuse' going into 'ind' is 'INFUSED'.
Can you help me to learn more?
(Other definitions for infused that I've seen before include "Did steep" , "poured in" , "as 27 [HERBAL TEA] did" , "Inculcated" , "as the tea maker did" .)
