Yes, tumble is a Scrabble word!

Verb

1. Fall down, as if collapsing

2. Cause to topple or tumble by pushing

3. Roll over and over, back and forth

4. Fly around

5. Fall apart

6. Throw together in a confused mass

7. Understand, usually after some initial difficulty

8. Fall suddenly and sharply

9. Put clothes in a tumbling barrel, where they are whirled about in hot air, usually with the purpose of drying

10. Suffer a sudden downfall, overthrow, or defeat

11. Do gymnastics, roll and turn skillfully

Noun

1. An acrobatic feat of rolling or turning end over end

2. A sudden drop from an upright position