disregard vs do by

disregard is a noun but do by is not a noun.

Word	Noun	Adjective	Verb	Adverb
disregard	Yes	No	Yes	No
do by	No	No	Yes	No

As verbs, do by is a hypernym of disregard; that is, do by is a word with a broader meaning than disregard:

Other hypernyms of disregard include handle, treat.

disregard (noun)	do by (noun)
willful lack of care and attention
lack of attention and due care

disregard (verb)	do by (verb)
give little or no attention to	interact in a certain way
bar from attention or consideration
refuse to acknowledge