1 a drinking-glass with no handle or foot (formerly with a rounded bottom so as not to stand upright).
2 an acrobat, esp. one performing somersaults.
3 (in full tumbler-drier) = tumble-drier.
4 a a pivoted piece in a lock that holds the bolt until lifted by a key. b a notched pivoted plate in a gunlock.
5 a kind of pigeon that turns over backwards in flight.
6 an electrical switch worked by pushing a small sprung lever.
7 a toy figure that rocks when touched.
8 = tumbling-barrel (see TUMBLE).
Derivatives:
tumblerful n. (pl. -fuls).
Useful english dictionary. 2012.