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

See also: unofficial

Antonym: officially

• chloramphenicol
• Chloranthaceae
• Chloranthus
• chlorate
• chlordiazepoxide
• chlorella
• chlorenchyma
• chlorhexidine
• chloric
• chloric acid
• chloride
• chloride of lime
• chlorinate
• chlorinated lime
• chlorination
• chlorine
• chlorine dioxide
• chlorine water
• chlorinity
• Chloris
• Chloris gayana
• Chloris truncata
• chlorite
• chloro-
• chloroacetophenone