Let one have it - was generous with money (6,3)
I believe the answer is:
lashed out
'let' is the definition.
I know nothing about this answer so I cannot judge whether it can be defined by this definition.
'one have it was generous with money' is the wordplay.
I cannot really understand how this works, but
'one' could be 'a' (a thing is one thing) and 'a' is found in the answer.
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is found within the answer.
'money' could be 'l' (L can mean 'pounds') and 'l' is found in the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for lashed out that I've seen before include "Was open-handed - or used one's fists?" , "Spent extravagantly" , "Attacked with words or blows - or whip?" , "getting castigated" , "struck at random" .)