One developing fuse to bombs (6)
I believe the answer is:
foetus
'one' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
'fuse to bombs' is the wordplay.
'bombs' indicates an anagram.
'fuse'+'to'='fuseto'
'fuseto' anagrammed gives 'FOETUS'.
'developing' is the link.
Can you help me to learn more?
(Other definitions for foetus that I've seen before include "Human embryo more than six weeks after conception" , "Unborn child" , "Developed embryo in the womb" , "Embryo of a mammal" , "Embryo in later stages" .)