know vs realise

know is a noun but realise is not a noun.

Word	Noun	Adjective	Verb	Adverb
know	Yes	No	Yes	No
realise	No	No	Yes	No

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

know: be cognizant or aware of a fact or a specific piece of information; possess knowledge or information about
realise: be fully aware or cognizant of

Other hyponyms of know include keep track, agnise, agnize, realize, recognise, recognize.

As verbs, realise is a hypernym of know; that is, realise is a word with a broader meaning than know:

Other hypernyms of know include agnise, agnize, realize, recognise, recognize.

know (noun)	realise (noun)
the fact of being aware of information that is known to few people

know (verb)	realise (verb)
be familiar or acquainted with a person or an object	perceive (an idea or situation) mentally
be cognizant or aware of a fact or a specific piece of information; possess knowledge or information about	be fully aware or cognizant of
know how to do or perform something	make real or concrete; give reality or substance to
have firsthand knowledge of states, situations, emotions, or sensations	expand or complete (a part in a piece of baroque music) by supplying the harmonies indicated in the figured bass
accept (someone) to be what is claimed or accept his power and authority	convert into cash; of goods and property
know the nature or character of	earn on some commercial or business transaction; earn as salary or wages
be able to distinguish, recognize as being different
perceive as familiar
have fixed in the mind
have sexual intercourse with