Humid - passionate (6)
I believe the answer is:
sultry
I believe this is a double definition.
'humid' is the first definition.
(synonyms)
'passionate' is the second definition.
(I've seen this before)
(Other definitions for sultry that I've seen before include "Oppressively hot and humid" , "Humid and oppressive" , "Oppressively humid - sensual" , "Passionate" , "Such weather is hot and oppressive" .)