A clothing item son put back dry (7)
I believe the answer is:
athirst
'dry' is the definition.
(I've seen this in another clue)
'a clothing item son put back' is the wordplay.
'clothing item' becomes 'thir' (I can't explain this - if you can you should believe this answer much more).
'son' becomes 's' (genealogical abbreviation for son).
'back' says to take the final letters (the letter at the back).
The final letter of 'put' is 't'.
'a'+'thir'+'s'+'t'='ATHIRST'
(Other definitions for athirst that I've seen before include "Dry" , "wanting a drink" , "Eager, avid (for)" , "having keen desire" , "Needing a drink (Old English)" .)