1. not able to penetrate or understand.   humid   ciliated   discrete   impenetrable   Hint Half-n-half Clue   2. based on induction or general inference from instances.   inductive   heterodox   carnivorous   impermeable   Half-n-half Clue   3. two-year long or every two years.   igneous   eccentric   herbivorous   biennial   Half-n-half Clue   4. grinding down or rubbing off.   asymmetric   finite   congruent   abrasive   Half-n-half Clue   5. surgically sterile or preventing infection.   brackish   impervious   indeterminate   aseptic   Half-n-half Clue   6. secure or resistant to.   immune   glacial   asymmetric   chronic   Half-n-half Clue   7. flying or radiating from a center.   centrifugal   homogeneous   dyspeptic   convex   Half-n-half Clue