mean vs signify

mean is a noun but signify is not a noun.

As verbs, signify is a hyponym of mean; that is, signify is a word with a more specific, narrower meaning than mean:

Other hyponyms of mean include stand for, represent, typify, symbolise, symbolize, import, spell, aim, get, aim, drive.

As verbs, mean and signify are synonyms defined as:

Other synonyms of mean include intend, stand for.

mean (noun)	signify (noun)
an average of n numbers computed by adding some function of the numbers and dividing by some function of n

mean (adjective)	signify (adjective)
approximating the statistical norm or average or expected value
characterized by malice
having or showing an ignoble lack of honor or morality
marked by poverty befitting a beggar
(used of persons or behavior) characterized by or indicative of lack of generosity
(used of sums of money) so small in amount as to deserve contempt
of no value or worth
very good; of the highest quality

mean (verb)	signify (verb)
mean or intend to express or convey	denote or connote
have as a logical consequence	convey or express a meaning
denote or connote	make known with a word or signal
have in mind as a purpose
have a specified degree of importance
intend to refer to
destine or designate for a certain purpose