Failure to see case for amateurish boat-builder (4)
I believe the answer is:
noah
'boat-builder' is the definition.
(I've seen this before)
'failure to see case for amateurish' is the wordplay.
'failure' becomes 'no' (I am not sure about this - if you are sure you should believe this answer much more).
'to see case for' suggests removing the centre (the letters which encase the others are used).
'amateurish' with its centre removed is 'ah'.
'no'+'ah'='NOAH'
Can you help me to learn more?
(Other definitions for noah that I've seen before include "The first boatbuilder?" , "His sons were Shem, Ham and Japheth" , "Hebrew patriarch who survived the Flood" , "Ark wright" , "Biblical arkwright" .)