1. Without official authorization
   "he had made some money on the side"
   - unofficially

Encyclopedia: On the side

• two-lane
• two-leafed
• two-leaved
• two-lipped
• two-lobed
• two-man saw
• two-man tent
• two-needled
• two-note call
• two-part
• two-party
• two-piece
• two-piece suit
• two-ply
• two-pronged
• two-seater
• two-sided
• two-spotted ladybug
• two-step
• two-stroke
• two-thirds
• two-tier bid
• two-time
• two-timer
• two-timing