rumination vs contemplation

rumination and contemplation both are nouns.

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

As nouns, rumination and contemplation are synonyms defined as:

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

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