Fumes (5)
'fumes' is the definition.
('reek' can be a synonym of 'fume')
This is the entire clue.
(Other definitions for reeks that I've seen before include "Smells very strongly" , "Stinks to high heaven" , "Smells bad" , "Gives off a strong unpleasant smell" , "Macgillycuddy's - -" .)
(Other definitions for smoke that I've seen before include "Fumigate; cigarette" , "cause of a cough?" , "'There's no . . . . . without fire'" , "Use a cigarette" , "Cure (food) - endanger health!" .)
(Other definitions for vapour that I've seen before include "Liquid in gas form" , "Gaseous state of matter" , "Particles suspended in air" , "Gaseous form of liquid substance" , "Visible steam or clouds" .)