Old shipbuilder's admitted by geisha only after review (5)
I believe the answer is:
noahs
'old shipbuilder's' is the definition.
'Noah's' can be an answer for 'shipbuilder's'. I'm unsure of the 'old' bit.
'admitted by geisha only after review' is the wordplay.
'NOAHS' is hidden back-to-front within the letters.
However, I'm not sure how the hidden word is indicated.
Can you help me to learn more?
(Other definitions for noahs that I've seen before include "- - Ark" , "& 13 Across Rescue vessel" .)