Having leant over, he had grabbed the fish (6)
I believe the answer is:
heeled
'having leant' is the definition.
I can't tell whether this definition defines the answer.
'over he had grabbed the fish' is the wordplay.
'over' means one lot of letters go next to another.
'had' becomes 'd' (in contractions e.g. 'I'd', 'you'd' etc).
'grabbed' indicates putting letters inside.
'the fish' becomes 'eel' (eel is a type of fish).
'he' put next to 'd' is 'hed'.
'hed' placed around 'eel' is 'HEELED'.
Can you help me to learn more?
(Other definitions for heeled that I've seen before include "Leant over" , "Be well shod thus to have money" , "As shoe may be repaired" , "Tilted; shod" , "Most shoes are" .)