1. (social) breaking any rules or boundaries
2. (art) creative endeavors that break as many rules as the artist sees fit to break.
Transgressive artists have sometimes disagreed with their being called "artists", as the term has become quite overinflated, cliched, and pretentious.
Detractors of "transgressives" have leveled the same charges at them.
My personal opinion added:
Transgression is not enough, but it's a real fuckin' good place to start. It should be done any way you want it, but I like mine with a side of fun.
1. Kyle grabbed his crotch and looked her up and down as an act of transgression, as if to say, "Fuck you, bitch."
2. Kyle videotaped this escapade as a work of transgression, as if to say "Fuck art and fuck you" via his art movie.