Model gains alien garments (4-3)
I believe the answer is:
twin-set
'model gains alien garments' is the definition.
I can't tell whether this defines the answer.
'model gains alien' is the wordplay.
'model' becomes 'T' (Ford Model T car).
'gains' becomes 'wins' ('win' can be a synonym of 'gain').
'alien' becomes 'et' (extra terrestrial).
't'+'wins'+'et'='TWIN-SET'
Can you help me to learn more?
(Other definitions for twin-set that I've seen before include "Wear associated with pearls?" , "Matching garments" , "Matching cardigan and jumper worn together" , "Two-piece outfit" .)