premeditate vs excogitate

premeditate and excogitate both are verbs.

Word	Noun	Adjective	Verb	Adverb
premeditate	No	No	Yes	No
excogitate	No	No	Yes	No

As verbs, excogitate is a hypernym of premeditate; that is, excogitate is a word with a broader meaning than premeditate:

Other hypernyms of premeditate include chew over, contemplate, meditate, mull, mull over, muse, ponder, reflect, ruminate, speculate, think over.

premeditate (verb)	excogitate (verb)
consider, ponder, or plan (an action) beforehand	reflect deeply on a subject
think or reflect beforehand or in advance	come up with (an idea, plan, explanation, theory, or principle) after a mental effort