Lyric discussion by Slavedriver 

Cover art for Stumbleine lyrics by Smashing Pumpkins, The

I think the title is almost certainly a pun on "Cymbeline", a Shakespearean play that was adapted as "The Injur'd Princess". Lots of intrigue, fakers attempting seduction, borderline rape etc (so standard Shakespearean fare).

Cymbeline is actually the king and father of the princess who is 'beshmirched', it comes from his inflexibility as a parent and denial of his daughter's affections to someone he thinks is of low breeding. So perhaps a reference to an offspring growing up and getting into trouble, and the friction between them and an overbearing parent who represents the 'unfairness' of the adult world and making a 'them vs us' situation between the grown-ups and the young.

A little too highbrow? ;)

@Slavedriver not highbrow at all, nice insight