n.

1. an acrobatic feat of rolling or turning end over end
2. a sudden drop from an upright position;
   spill, fall
   
   • he had a nasty spill on the ice

v.

1. fall down, as if collapsing;
   topple
   
   • The tower of the World Trade Center tumbled after the plane hit it
2. cause to topple or tumble by pushing;
   topple, tip
3. roll over and over, back and forth
4. fly around;
   whirl, whirl around
   
   • The clothes tumbled in the dryer";  "rising smoke whirled in the air
5. fall apart;
   crumble, crumple, break down, collapse
   
   • the building crumbled after the explosion
   • Negotiations broke down
6. throw together in a confused mass
   
   • They tumbled the teams with no apparent pattern
7. understand, usually after some initial difficulty;
   catch on, get wise, get onto, latch on, cotton on, twig, get it
   
   • She didn't know what her classmates were plotting but finally caught on
8. fall suddenly and sharply
   
   • Prices tumbled after the devaluation of the currency
9. put clothes in a tumbling barrel, where they are whirled about in hot air, usually with the purpose of drying
   
   • Wash in warm water and tumble dry
10. suffer a sudden downfall, overthrow, or defeat
11. do gymnastics, roll and turn skillfully