vicennial /vī-senˈyəl/

1. Lasting, or coming at the end of, twenty years
2. Occurring every twenty years

• goodfellowships
• good folk
• good for anything
• good form
• good-for-nothing
• good-for-nothings
• good for you
• Good Friday
• good gracious
• good grief
• good hands
• good heavens
• good humour
• good-humoured
• good-humouredly
• good-humouredness
• good hunting
• goodier
• goodies
• goodiest
• goodiness
• goodinesses
• goodish
• good-King-Henry
• good-lack