Nice about ship worker being constant (9)
I believe the answer is:
incessant
'being constant' is the definition.
(I've seen this in another clue)
'nice about ship worker' is the wordplay.
'about' indicates anagramming the letters.
'ship' becomes 'SS' (prefix in ship names eg SS Great Britain).
'worker' becomes 'ant' (worker is a type of ant).
'nice' anagrammed gives 'ince'.
'ince'+'ss'+'ant'='INCESSANT'
(Other definitions for incessant that I've seen before include "Nine casts (anag) - nonstop" , "happening all the time" , "Unending" , "without a break" , "Constant, unremitting" .)