Great hotel for swimming on the whole (10)
I believe the answer is:
altogether
'on the whole' is the definition.
(synonyms)
'great hotel for swimming' is the wordplay.
'for swimming' indicates anagramming the letters (letters swim around).
'great'+'hotel'='greathotel'
'greathotel' with letters rearranged gives 'ALTOGETHER'.
(Other definitions for altogether that I've seen before include "nude in this" , "Completely, in total" , "Quite" , "totally" , "Completely, on the whole" .)