One being fussy about new necklace adornment (7)
I believe the answer is:
pendant
'adornment' is the definition.
(I know that pendant is a type of adornment)
'one being fussy about new necklace' is the wordplay.
I cannot quite see how this works, but
'one' could be 'an' (an apple is one apple) and 'an' is present in the answer.
'being' could be 'end' (end is a kind of being) and 'end' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for pendant that I've seen before include "Ornament hanging from a piece of jewellery" , "Ornament hanging from necklace" , "item suspended" , "One hung by the neck" , "Panted after learned one" .)