Genesis builder (4)
I believe the answer is:
noah
'genesis builder' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for noah that I've seen before include "Legendary Biblical boat-builder" , "He survived 40 days and 40 nights of rain" , "zoo keeper" , "Great Biblical boatman" , "Ark wright" .)