Family mostly moonstruck by dressing gown (6)
I believe the answer is:
kimono
'dressing gown' is the definition.
(I've seen this in another clue)
'family mostly moonstruck by' is the wordplay.
'family' becomes 'kin' (synonyms).
'mostly' means to remove the last letter.
'moonstruck' becomes 'mono' (I am not sure about this - if you are sure you should believe this answer much more).
'by' says to put letters next to each other.
'kin' with its last letter taken away is 'ki'.
'ki'+'mono'='KIMONO'
Can you help me to learn more?
(Other definitions for kimono that I've seen before include "Traditional Japanese robe with wide sleeves" , "Loose robe, originally Japanese" , "Asian garment" , "Japanese wrap" , "Japanese style of robe or gown" .)