Synonyms for Impenetrable

Synonyms starting with letter R

• resistant

  impervious, property
• recondite

  incomprehensible
• rigid
• restricted

  restrictive
• rock-hard
• rank
• restrictive
• rocky
• rainproof
• rocklike
• repellent
• raintight
• ropy
• refractory
• rambling
• round-about
• replete
• roily
• rare
• rugged
• rock hard
• round about
• rich
• riotous
• rampant
• rarefied
• resolute
• rooted
• remote