The Collaborative International Dictionary of English v.0.48:
Tumble \Tum"ble\ (t[u^]m"b'l), v. i. [imp. & p. p. Tumbled
(t[u^]m"b'ld); p. pr. & vb. n. Tumbling (t[u^]m"bl[i^]ng).]
[OE. tumblen, AS. tumbian to turn heels over head, to dance
violently; akin to D. tuimelen to fall, Sw. tumla, Dan.
tumle, Icel. tumba; and cf. G. taumeln to reel, to stagger.]
1. To roll over, or to and fro; to throw one's self about;
as, a person in pain tumbles and tosses.
2. To roll down; to fall suddenly and violently; to be
precipitated; as, to tumble from a scaffold.
He who tumbles from a tower surely has a greater
blow than he who slides from a molehill. --South.
3. To play tricks by various movements and contortions of the
body; to perform the feats of an acrobat. --Rowe.
To tumble home (Naut.), to incline inward, as the sides of
a vessel, above the bends or extreme breadth; -- used esp.
in the phrase tumbling home. Cf. Wall-sided.