Pietism rhymes with:
defeatism, baptism, defeatism, irredentism, vigilantism, absenteeism, amateurism, 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, polymorphism, polytheism, pugilism, realism, sadism, sexism, surrealism, taoism, theism, truism, vandalism, vegetarianism, vigilantism, voyeurism
Pietism sounds like:
patagonia, patagonian, patchen, patchin, pathogen, patteson, pattison, petitjean, pettijohn, pidgeon, pitchman, pitchmen, pitkin, pitswon, pitzen, potassium