Twice league sides bear heavy rain on falling (5,4)
I believe the answer is:
lemon sole
'falling' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'twice league sides bear heavy rain on' is the wordplay.
I cannot really see how this works, but
'league' could be 'l' (abbreviation) and 'l' is found within the answer.
'on' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for lemon sole that I've seen before include "Edible flatfish" , "Flatfish, valued as food" , "Tasty plaice of citrus origin?" , "Another tasty flatfish like lone citrus fruit" , "swimmer" .)