Synonyms for Impenetrable

Synonyms starting with letter O

• obscure

  incomprehensible, non-transparent, illegible
• opaque

  non-transparent, incomprehensible
• occult
• overgrown

  dense
• obstructed
• obfuscated
• odd
• oracular
• oblique
• overcast
• obtuse
• out of reach
• ossified
• obdurate
• out of sight
• otherworldly
• out-of-bounds
• obscurely
• orphic
• overlooked
• over one's head