junior vs petty

junior and petty both are nouns.

Word	Noun	Adjective	Verb	Adverb
junior	Yes	Yes	No	No
petty	Yes	Yes	No	No

junior (noun)	petty (noun)
the younger of two persons	larceny of property having a value less than some amount (the amount varies by locale)
a third-year undergraduate
term of address for a disrespectful and annoying male

junior (adjective)	petty (adjective)
younger; lower in rank; shorter in length of tenure or service	inferior in rank or status
used of the third or next to final year in United States high school or college	contemptibly narrow in outlook
including or intended for youthful persons	(informal) small and of little importance