Antonyms of adj penetrable

2 senses of penetrable

Sense 1
penetrable (vs. impenetrable) -- (admitting of penetration or passage into or through; "a penetrable wall"; "penetrable defenses")

impenetrable (vs. penetrable) -- (not admitting of penetration or passage into or through; "an impenetrable fortress"; "impenetrable rain forests")
        => dense, thick -- (hard to pass through because of dense growth; "dense vegetation"; "thick woods")

Sense 2
penetrable -- (capable of being penetrated; "penetrable defenses")

INDIRECT (VIA vulnerable) -> invulnerable -- (immune to attack; impregnable; "gunners raked the beach from invulnerable positions on the cliffs")

Similarity of adj penetrable

2 senses of penetrable

Sense 1
penetrable (vs. impenetrable) -- (admitting of penetration or passage into or through; "a penetrable wall"; "penetrable defenses")

Sense 2
penetrable -- (capable of being penetrated; "penetrable defenses")
       => vulnerable (vs. invulnerable) -- (susceptible to attack; "a vulnerable bridge")