Hoping to gain, lay out trendy underwear (6)
I believe the answer is:
invest
'hoping to gain lay' is the definition.
I can't tell whether this defines the answer.
'trendy underwear' is the wordplay.
'trendy' becomes 'in' ('in' can mean fashionable).
'underwear' becomes 'vest'.
'in'+'vest'='INVEST'
'out' acts as a link.
Can you help me to learn more?
(Other definitions for invest that I've seen before include "Put money into business for profit" , "Put money into in hopes of a return" , "Put money into shares, property, etc" , "Contribute money in hope of a return" , "as Greeks did to Troy?" .)