1. Without official authorization
   - on the side 
2. Not in an official capacity
   "unofficially, he serves as the treasurer"

See also: unofficial

Antonym: officially

• candlestick
• candlestick tulip
• candlewick
• candlewood
• candor
• candour
• candy
• candy apple
• candy bar
• candy cane
• candy corn
• candy egg
• candy kiss
• candy store
• candy striper
• candy thermometer
• candy-ass
• candy-like
• candy-scented
• candyfloss
• candymaker
• candytuft
• candyweed
• cane
• cane blight