im ‧ per ‧ ma ‧ nent /ɪmˈpɜːmənənt $ -ɜːr-/ BrE AmE adjective formal
not staying the same forever SYN temporary OPP permanent :
single-storey structures, built from cheap and impermanent materials
—impermanence noun [uncountable] :
His philosophy stressed the impermanence of the world.