Majority yearn to have union involved creating growth? (9)
I believe the answer is:
moustache
'growth?' is the definition.
(I have seen 'Facial growth' mean 'moustache' so perhaps 'growth' could also mean 'moustache')
'majority yearn to have union involved' is the wordplay.
'majority' becomes 'most' (most of a group).
'yearn' becomes 'ache' (synonyms).
'to have' is a charade indicator (letters next to each other).
'union' becomes 'U' (common abbreviation as in Trades Union Congress).
'involved' indicates putting letters inside.
'most'+'ache'='mostache'
'mostache' going around 'u' is 'MOUSTACHE'.
'creating' acts as a link.
(Other definitions for moustache that I've seen before include "whiskers" , "Facial feature" , "Food trap" , "Facial hair growth" , "legacy of Zapata?" .)