A party gets navy on deck (5)
I believe the answer is:
adorn
'deck' is the definition.
(thesaurus)
'a party gets navy' is the wordplay.
'party' becomes 'do' (do is a kind of party).
'gets' is a charade indicator (letters next to each other).
'navy' becomes 'rn' (abbreviation for Royal Navy).
'a'+'do'+'rn'='ADORN'
'on' acts as a link.
(Other definitions for adorn that I've seen before include "Beautify - decorate - enhance" , "Improve appearance" , "get dressed!" , "Bedeck" , "dress" .)