learner vs memoriser

learner and memoriser both are nouns.

Word	Noun	Adjective	Verb	Adverb
learner	Yes	No	No	No
memoriser	Yes	No	No	No

As nouns, memoriser is a hyponym of learner; that is, memoriser is a word with a more specific, narrower meaning than learner:

learner: someone (especially a child) who learns (as from a teacher) or takes up knowledge or beliefs
memoriser: a person who learns by rote

Other hyponyms of learner include memorizer, quick study, sponge, dweeb, grind, nerd, swot, wonk, tutee.

learner (noun)	memoriser (noun)
someone (especially a child) who learns (as from a teacher) or takes up knowledge or beliefs	a person who learns by rote
works for an expert to learn a trade