In Hebrew, the feminine noun aveira or averah (Hebrew עבירה pl. aveirot ) is a term for transgression or sin against man or God. The word comes from the Hebrew root ayin- bet- resh, meaning to pass or cross over with the implied meaning of transgressing from a moral boundary. An aveira may be trivial or serious.
It is viewed by many that an aveira is the opposite of a mitzvah (commandment, often viewed as a good deed), but all aveirot are actually the transgressions of one of the 365 "negative commandments". (see 613 commandments.)