mental process vs cognitive operation

mental process and cognitive operation both are nouns.

Word	Noun	Adjective	Verb	Adverb
mental process	Yes	No	No	No
cognitive operation	Yes	No	No	No

As nouns, mental process and cognitive operation are synonyms defined as:

mental process and cognitive operation: (psychology) the performance of some composite cognitive activity; an operation that affects mental contents

Other synonyms of mental process include cognitive process, operation, process.

mental process (noun)	cognitive operation (noun)
(psychology) the performance of some composite cognitive activity; an operation that affects mental contents	(psychology) the performance of some composite cognitive activity; an operation that affects mental contents