Amateurism rhymes with:
absenteeism, anthropomorphism, antidisestablishmentarianism, atavism, baptism, buddhism, careerism, cubism, culturalism, defeatism, deism, dimorphism, dwarfism, ethnocentrism, extremism, idealism, irredentism, isomorphism, jainism, jingoism, marxism, masochism, mccarthyism, modalism, monism, monotheism, multiculturalism, multilateralism, nazism, nestorianism, parliamentarianism, pietism, polymorphism, polytheism, pugilism, realism, sadism, sexism, surrealism, taoism, theism, truism, vandalism, vegetarianism, vigilantism, voyeurism
Amateurism sounds like:
andersen, anderson, andersson, andreasen, andreason, andreassen, andresen, andriessen, androgyny