1. Without speaking
   - mutely, wordlessly, taciturnly 
2. Without a sound
   - noiselessly, soundlessly

See also: silent

• streaky
• stream
• stream of consciousness
• stream orchid
• streambed
• streamer
• streamer fly
• streaming
• streaming audio
• streaming video
• streamlet
• streamline
• streamline flow
• streamlined
• streamliner
• streel
• Streep
• street
• street address
• street arab
• street child
• street cleaner
• street clothes
• street corner
• street cred