jar against vs knock against

jar against and knock against both are verbs.

Word	Noun	Adjective	Verb	Adverb
jar against	No	No	Yes	No
knock against	No	No	Yes	No

As verbs, jar against and knock against are synonyms defined as:

Other synonyms of jar against include bump into, butt against, run into.

jar against (verb)	knock against (verb)
collide violently with an obstacle	collide violently with an obstacle