sub·side / səbˈsīd/ • v. [intr.] 1. become less intense, violent, or severe: I'll wait a few minutes until the storm subsides. ∎ lapse into silence or inactivity: Fred opened his mouth to protest again, then subsided.2. (of water) go down to a lower or the normal level: the floods subside almost as quickly as they arise. ∎ (of the ground) cave in; sink: the island is subsiding. ∎ (of a swelling) reduce until gone: it took seven days for the swelling to subside completely.