excogitate vs think over

excogitate and think over both are verbs.

Word	Noun	Adjective	Verb	Adverb
excogitate	No	No	Yes	No
think over	No	No	Yes	No

As verbs, excogitate and think over are synonyms defined as:

Other synonyms of excogitate include chew over, contemplate, meditate, mull, mull over, muse, ponder, reflect, ruminate, speculate.

excogitate (verb)	think over (verb)
reflect deeply on a subject	reflect deeply on a subject
come up with (an idea, plan, explanation, theory, or principle) after a mental effort