Old sailor in North Sea not getting rest (4)
I believe the answer is:
noah
'old sailor' is the definition.
'noah' can be an answer for 'sailor' (from bible: Noah's Ark). I am not sure about the 'old' bit.
'in north sea not getting rest' is the wordplay.
'in' is an insertion indicator.
'not getting' suggests deleting specific letters.
'north' enclosing 'sea' is 'nortseah'.
'nortseah' with 'rest' taken out is 'NOAH'.
Can you help me to learn more?
(Other definitions for noah that I've seen before include "biblical character" , "He built an ark" , "Legendary Biblical boat-builder" , "Great Biblical boatman" , "Biblical shipbuilder" .)