Hot tub (7)
(Other definitions for jacuzzi that I've seen before include "Whirlpool bathtub with underwater jets" , "Bath with water jets" , "Whirly bath" , "Bath in which water is mechanically agitated" , "Modern bath with underwater jets" .)
'hot tub' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for spa that I've seen before include "Water source" , "Bath - mineral water spring" , "Resort with mineral water spring" , "Watering place" , "Health resort near a spring" .)