planning vs mentation

planning and mentation both are nouns.

Word	Noun	Adjective	Verb	Adverb
planning	Yes	No	No	No
mentation	Yes	No	No	No

As nouns, mentation is a hypernym of planning; that is, mentation is a word with a broader meaning than planning:

planning: the cognitive process of thinking about what you will do in the event of something happening
mentation: the process of using your mind to consider something carefully

Other hypernyms of planning include cerebration, intellection, thinking, thought, thought process.

planning (noun)	mentation (noun)
an act of formulating a program for a definite course of action	the process of using your mind to consider something carefully
the act or process of drawing up plans or layouts for some project or enterprise
the cognitive process of thinking about what you will do in the event of something happening