He made no exclamation when there was a flood (4)
I believe the answer is:
'he' is the definition.
'no exclamation when there was a flood' is the wordplay.
I cannot quite understand how this works, but
'no' could be 'o' (resembles 0 - 'no' can mean 'zero') and 'o' is present in the answer.
'exclamation' could be 'ah' and 'ah' is present in the answer.
A single letter 'n' remains which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'made' is the link.
Can you help me to learn more?
(Other definitions for noah that I've seen before include "A very early sailor" , "Biblical builder of great ship" , "The first known boat builder (4)" , "Early boatman" , "Biblical skipper during the Flood" .)