Giant relations wearing brown (5)
I believe the answer is:
titan
'giant' is the definition.
(I know that giant can be written as titan)
'relations wearing brown' is the wordplay.
'relations wearing' becomes 'ti' (I can't explain this - if you can you should give a lot more credence to this answer).
'brown' becomes 'tan' (tan is a kind of brown).
'ti'+'tan'='TITAN'
Can you help me to learn more?
(Other definitions for titan that I've seen before include "Atlas, say" , "one of great importance" , "Huge(ly important) type" , "Giant god of Gr. myth" , "Moon of Saturn visited by the Huygens probe" .)