sleeping (figuratively); lying inactive; latent
The volcano had been dormant for many years and was considered so safe that groups of tourists would walk right into its inactive crater.
dormire (to sleep) (Latin)
Dormant is like DoorMat which SLEEPS on the floor. so INACTIVE see the word DORMant, DORM is a dormitory a place to sleep. so if you are sleeping you are inactive or lethargic.