Tea's served in this empty galley that's unpleasantly humid (5)

I believe the answer is:

muggy

I'm a little stuck... Click here to teach me more about this clue!

'unpleasantly humid' is the definition.
(I've seen this in another clue)

I can't explain the rest of the clue.

(Other definitions for muggy that I've seen before include "Unpleasantly humid" , "close" , "Oppressively humid" , "Warm and humid" , "Warm and wet" .)

I've seen this clue in The Independent.

Want a hint initially instead of a full solution? Install my app