vicennial /vī-senˈyəl/

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

• whillywhaw
• whillywhawed
• whillywhawing
• whillywhaws
• whilom
• whilst
• whim
• whimberries
• whimberry
• whimbrel
• whimbrels
• whimmed
• whimmier
• whimmiest
• whimming
• whimmy
• whimper
• whimpered
• whimperer
• whimperers
• whimpering
• whimperingly
• whimperings
• whimpers
• whimple