Extremely young to wear tacky scent and brood? (7)
I believe the answer is:
cygnets
'brood?' is the definition.
(young swans - brood can mean young birds)
'extremely young to wear tacky scent' is the wordplay.
'extremely' says to hollow out the word (remove centre letters) (only the extremes of the word are used).
'to wear' indicates putting letters inside (to wear something is to be covered up by it).
'tacky' is an anagram indicator (a crude or tacky form of the letters).
'young' with its centre removed is 'yg'.
'scent' anagrammed gives 'cnets'.
'yg' put inside 'cnets' is 'CYGNETS'.
'and' acts as a link.
(Other definitions for cygnets that I've seen before include "Young swans" , "Young birds" .)