1. In a harmfully insidious manner
   "these drugs act insidiously"
   - perniciously

See also: insidious

• Sidney James Webb
• Sidney Poitier
• Sidney Webb
• Sidon
• Sidonie-Gabrielle Claudine Colette
• Sidonie-Gabrielle Colette
• SIDS
• siege
• siege of Orleans
• siege of Syracuse
• siege of Vicksburg
• siege of Yorktown
• Siege Perilous
• Siegfried
• Siegfried line
• siemens
• sienna
• sierra
• Sierra Leone
• Sierra Leone monetary unit
• Sierra Leonean
• Sierra lodgepole pine
• Sierra Madre Occidental
• Sierra Madre Oriental
• Sierra Nevada