grok vs tumble

grok is not a noun while tumble is a noun.

Word	Noun	Adjective	Verb	Adverb
grok	No	No	Yes	No
tumble	Yes	No	Yes	No

As verbs, tumble is a hyponym of grok; that is, tumble is a word with a more specific, narrower meaning than grok:

Other hyponyms of grok include figure, catch on, cotton on, get it, get onto, get wise, latch on, twig, intuit, digest.

grok (noun)	tumble (noun)
	an acrobatic feat of rolling or turning end over end
	a sudden drop from an upright position

grok (verb)	tumble (verb)
get the meaning of something	do gymnastics, roll and turn skillfully
	fall suddenly and sharply
	suffer a sudden downfall, overthrow, or defeat
	put clothes in a tumbling barrel, where they are whirled about in hot air, usually with the purpose of drying
	understand, usually after some initial difficulty
	throw together in a confused mass
	fall down, as if collapsing
	fall apart
	roll over and over, back and forth
	cause to topple or tumble by pushing
	fly around