pertain vs regard

pertain is not a noun while regard is a noun.

Word	Noun	Adjective	Verb	Adverb
pertain	No	No	Yes	No
regard	Yes	No	Yes	No

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

pertain (noun)	regard (noun)
	a long fixed look
	(usually preceded by `in') a detail or point
	paying particular notice (as to children or helpless people)
	an attitude of admiration or esteem
	(usually plural) a polite expression of desire for someone's welfare
	a feeling of friendship and esteem
	the condition of being honored (esteemed or respected or well regarded)

pertain (verb)	regard (verb)
be a part or attribute of	deem to be
be relevant to	look at attentively
	connect closely and often incriminatingly