petty vs stealing

petty and stealing both are nouns.

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

As nouns, stealing is a hypernym of petty; that is, stealing is a word with a broader meaning than petty:

petty: larceny of property having a value less than some amount (the amount varies by locale)
stealing: the act of taking something from someone unlawfully

Other hypernyms of petty include larceny, theft, thievery, thieving.

petty (noun)	stealing (noun)
larceny of property having a value less than some amount (the amount varies by locale)	the act of taking something from someone unlawfully
	avoiding detection by moving carefully

petty (adjective)	stealing (adjective)
inferior in rank or status
contemptibly narrow in outlook
(informal) small and of little importance