Bother with sailors on deck (5)
I believe the answer is:
adorn
'deck' is the definition.
(thesaurus)
'bother with sailors on' is the wordplay.
'bother with' becomes 'ado' (I've seen this in other clues).
'sailors' becomes 'rn' (abbreviation for Royal Navy).
'on' says to put letters next to each other.
'ado'+'rn'='ADORN'
(Other definitions for adorn that I've seen before include "Deck" , "Bedeck" , "Festoon" , "Make more attractive" , "get dressed!" .)