Synonyms for Impenetrable

Synonyms starting with letter S

• solid

  dense, characteristic, property
• strong

  property
• secure

  property
• sealed

  waterproof, state
• secret

  exclusive
• substantial

  dense
• strange

  unexplainable, unaccountable
• stiff
• stony
• secretive

  exclusive
• sphinxlike
• safe

  secure
• solidified
• serpentine
• sibylline

  incomprehensible
• supernatural
• steely
• soupy
• short
• sturdy
• sophisticated
• sound
• smoky
• steadfast
• staunch
• showerproof
• syrupy
• set
• sloppy
• sinuous
• snarled
• several
• swarming
• shrunken
• shut
• skintight
• slammed
• smothering
• snapped
• stopped up