1. Synonymous to synonymous but larger and therefore significantly more awesome. Can be used randomly to describe events or situations that are similar. It can also be used sardonically when they aren't necessarilyidentical or even related.
2. Any person, place, thing or idea that is AS BIG AS A SUMO (wrestler)
Yeah I hate it it when Sally whore's herself out like that.
What? I was talking about when that dude puked everywhere!
Oh right. I guess the two are pretty sumonomous.