Other forms: roistering; roistered; roisters
To roister is to celebrate in a noisy way with other people. You'll be tempted to roister with friends after your favorite team wins the Super Bowl, but keep it down once it's late and people are sleeping!
Hooting and hollering after a sports victory is a good example of roistering. It's wild, loud, celebratory fun. If you've been in a college town when the basketball team wins the championship, you've probably seen throngs of students roister in the streets. This kind of boisterous revelry can turn obnoxious or even destructive, and the word's root suggests this; roister is from the Old French ruiste, "boorish or uncouth," from the Latin rusticus, "rough or coarse."