Very hot and humid (8)
I believe the answer is:
tropical
'very hot and humid' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for tropical that I've seen before include "April-Oct, unusually humid and very hot" , "Found in Cancer or Capricorn" , "Originating from hotter parts of the earth" , "Middle-earth" , "it could be too hot" .)