Ambassador takes part in maiden voyage (5)
I believe the answer is:
envoy
'ambassador' is the definition.
(I've seen this in another clue)
'part in maiden voyage' is the wordplay.
'part in' indicates the answer is hidden within the clue.
'ENVOY' is hidden in the letters of 'maiden voyage'.
'takes' acts as a link.
(Other definitions for envoy that I've seen before include "final words in writing" , "Emissary" , "Diplomat" , "Legate" , "Diplomatic messenger" .)