Flood runs through at lower level (5)
I believe the answer is:
drown
'flood' is the definition.
(I've seen this before)
'runs through at lower level' is the wordplay.
I cannot quite see how this works, but
'runs' could be 'r' (cricket abbreviation) and 'r' is present in the answer.
'lower' could be 'down' (synonyms) and 'down' is present in the remaining letters.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for drown that I've seen before include "Become submerged" , "Flood; kill" , "Swamp" , "Sink" , "Submerge, maybe fatally" .)