Spa city (4)
I believe the answer is:
bath
'spa city' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for bath that I've seen before include "Stopper for hole (don't let 8 through it!)" , "Large tub" , "It may be run" , "Georgian city" , "city that may or may not chime with 27 [HEARTH]" .)