contemplation vs rumination

contemplation and rumination both are nouns.

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

As nouns, contemplation and rumination are synonyms defined as:

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

contemplation (noun)	rumination (noun)
a long and thoughtful observation	regurgitation of small amounts of food; seen in some infants after feeding
a calm, lengthy, intent consideration	(of ruminants) chewing (the cud)
	a calm, lengthy, intent consideration