Entry 1 sense Webster, 1913 Penetrable · Pen·e·tra·ble · IPA /ˈpɛnətɹəbəl/ 01 a. Capable of being penetrated, entered, or pierced. Used also figuratively. 1. Capable of being penetrated, entered, or pierced. Used also figuratively. “And pierce his only penetrable part.” — Dryden. “I am not made of stones, But penetrable to your kind entreats.” — Shak.