"Jar against" is a phrase that describes a sudden impact or jolt, often resulting in a loud or jarring noise. There are many synonyms that can be used to convey the same idea, including bump, bang, thud, crash, clash, and slam. These words differ slightly in their connotations, with some suggesting a softer impact (bump) and others indicating a more violent collision (crash, slam). Other similar words include collide, strike, hit, and jolt. Depending on the context, certain synonyms may be more appropriate than others, so it's important to choose a word that accurately conveys the intended meaning.