Nautical clock by New Zealander lacking nothing (8)
I believe the answer is:
maritime
'nautical' is the definition.
('maritime' can be a synonym of 'nautical')
'clock by new zealander lacking nothing' is the wordplay.
'clock' becomes 'time' (time clock is a kind of clock**).
'by' says to put letters next to each other.
'new zealander' becomes 'maori' (I've seen this before).
'lacking' indicates named letters should be taken away.
'nothing' becomes 'o' (looks like zero - 0).
'maori' with 'o' removed is 'mari'.
'time' after 'mari' is 'MARITIME'.
(Other definitions for maritime that I've seen before include "beside the sea" , "Concerned with the main" , "Connected to the sea and sea-faring" , "Naval" , "Coastal" .)