thoughtfulness vs rumination

thoughtfulness and rumination both are nouns.

Word	Noun	Adjective	Verb	Adverb
thoughtfulness	Yes	No	No	No
rumination	Yes	No	No	No

As nouns, thoughtfulness and rumination are synonyms defined as:

Other synonyms of thoughtfulness include contemplation, musing, reflection, reflexion.

thoughtfulness (noun)	rumination (noun)
a considerate and thoughtful act	regurgitation of small amounts of food; seen in some infants after feeding
the trait of thinking carefully before acting	(of ruminants) chewing (the cud)
kind and considerate regard for others	a calm, lengthy, intent consideration
a calm, lengthy, intent consideration