Arrive, relaxed, around waterway (5)
I believe the answer is:
river
'waterway' is the definition.
(thesaurus)
'arrive relaxed around' is the wordplay.
'around' indicates a hidden word.
'RIVER' is hidden in the letters of 'arrive relaxed'.
(Other definitions for river that I've seen before include "Waterway" , "Exe, Po" , "Moon - - (song)" , "Eg, Thames or Nile" , "x or y, so to speak" .)