One in on grass crop heads of mafia outfit will eagerly rob (5)
I believe the answer is:
mower
'one in on grass crop' is the definition.
I can't judge whether this defines the answer.
'heads of mafia outfit will eagerly rob' is the wordplay.
'heads of' says to take the initial letters.
The initial letters of 'mafia outfit will eagerly rob' is 'MOWER'.
Can you help me to learn more?
(Other definitions for mower that I've seen before include "Gardening equipment" , "Gardening machine" , "Machine for cutting grass" , "Lawn cutter" , "Grass-cutter" .)