1. In an optional manner
   "this rule is applied optionally"

See also: optional

Antonym: obligatorily

• wine-coloured
• wine-maker's yeast
• wine-red
• wineberry
• wineglass
• wineglass heel
• winegrower
• winemaker
• winemaking
• winepress
• winery
• Winesap
• wineskin
• winey
• Winfield Scott
• Winfred
• wing
• wing case
• wing chair
• wing commander
• wing elm
• wing flat
• wing loading
• wing screw
• wing shooting