Reported space for watery fluid (5)
I believe the answer is:
rheum
'watery fluid' is the definition.
(I've seen this before)
'reported space' is the wordplay.
'reported' shows a homophone (sound like).
'space' becomes 'room' (enough space or room to do something).
'room' is a homophone of 'RHEUM'.
'for' is the link.
(Other definitions for rheum that I've seen before include "sign of illness" , "Tears of a cold" , "Moist discharge from nose or eyes" , "nasal drops" , "Watery mucous discharge" .)