Body of water one might, reportedly, glimpse from here (5,3)
I believe the answer is:
irish sea
'one might reportedly glimpse from here' is the definition.
The definition suggests a singular noun which matches the answer.
'body of water' is the wordplay.
'body of' becomes 'irish' (I can't explain this - if you can you should give a lot more credence to this answer).
'water' becomes 'sea' (the sea is water).
'irish'+'sea'='IRISH SEA'
Can you help me to learn more?
(Other definitions for irish sea that I've seen before include "Large quantity of water" , "It separates Ireland from Britain" , "Water west of Wales" , "Waters around IOM" , "Man's found here" .)