Sweltering bridge player truly confused (6)
I believe the answer is:
sultry
'sweltering' is the definition.
('sultry' can be a synonym of 'sweltering')
'bridge player truly confused' is the wordplay.
'bridge player' becomes 's'.
'confused' indicates anagramming the letters.
'truly' anagrammed gives 'ultry'.
's'+'ultry'='SULTRY'
(Other definitions for sultry that I've seen before include "Sweltering, close and oppressive" , "Close -- sensual" , "Oppressively humid - sensual" , "Hot and steamy" , "Such weather is close and oppressive" .)