Hard fall may reveal this moral (9)
I believe the answer is:
'hard fall' is the definition.
'hailstorm' can be an answer for 'fall' (I have seen 'Fall of ice ' mean 'hailstorm' so perhaps 'fall' could also mean 'hailstorm'). I'm unsure of the 'hard' bit.
'reveal this moral' is the wordplay.
'reveal' indicates an anagram.
'thismoral' anagrammed gives 'HAILSTORM'.
'may' acts as a link.
Can you help me to learn more?
(Other definitions for hailstorm that I've seen before include "rough weather" , "when Sky drops The Stones?" , "Violent shower" , "Cold shower" , "Frozen rain squall" .)