Is “Tumbler” a Scrabble word?
Yes
TUMBLER
Valid in at least one Scrabble dictionary
Valid in these dictionaries
SOWPODS / CSW
Scrabble UK & International
TWL / NWL
Scrabble North America
Large English Dictionary
General English word list
Meaning of Tumbler
/ˈtʌmblɚ/
noun
1.One who tumbles; one who plays tricks by various motions of the body; an acrobat.
2.A movable obstruction in a lock, consisting of a lever, latch, wheel, slide, or the like, which must be adjusted to a particular position by a key or other means before the bolt can be thrown in locking or unlocking.
3.A rotating device for smoothing and polishing rough objects, placed inside it, on relatively small parts.