Clothes become dated? Rubbish (7)
I believe the answer is:
garbage
'rubbish' is the definition.
(both can mean refuse or trash)
'clothes become dated?' is the wordplay.
'clothes' becomes 'garb' (garb is a kind of clothes).
'become dated?' becomes 'age' (I can't explain this - if you can you should believe this answer much more).
'garb'+'age'='GARBAGE'
Can you help me to learn more?
(Other definitions for garbage that I've seen before include "Worthless matter" , "'Refuse, rubbish (7)'" , "A beggar? - that may be rubbish" , "Pop group; rubbish" , "Waste, refuse" .)