Close match for clothing you may go out in (7)
I believe the answer is:
nightie
'clothing you may go out in' is the definition.
I can't tell whether this definition defines the answer.
'close match' is the wordplay.
'close' becomes 'nigh' (similar in meaning).
'match' becomes 'tie' (I've seen this before).
'nigh'+'tie'='NIGHTIE'
'for' acts as a link.
Can you help me to learn more?
(Other definitions for nightie that I've seen before include "Familiar bed-wear for woman" , "Light sleeping gown" , "Bedtime habit" , "Bed attire (colloq.)" , "put on at end of day?" .)