You relaxed around river (3)
I believe the answer is:
ure
'river' is the definition.
(river in Yorkshire)
'you relaxed around' is the wordplay.
'around' indicates a hidden word.
'URE' can be found hidden inside 'you relaxed'.
(Other definitions for ure that I've seen before include "Ripon's river" , "Midge --, singer" , "North Yorkshire river" , "River of N. Yorkshire" , "River at Ripon" .)