Dashing person has known lady primarily for the time that dampens fire (9)
I believe the answer is:
sprinkler
'that dampens fire' is the definition.
(I've seen this before)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for sprinkler that I've seen before include "Lawn waterer" , "Device attached to a garden hose for watering" , "Lawn watering device" , "Fire extinguisher" , "that dampens fire" .)