1. periodic shedding (of leaves).   dyspeptic   caustic   finite   deciduous   Hint Half-n-half Clue   2. occurring at the same time.   herbivorous   abrasive   concurrent   biennial   Half-n-half Clue   3. practicable or possible.   dyspeptic   carnivorous   dorsal   feasible   Half-n-half Clue   4. impervious or unpassable.   alimentary   fundamental   empirical   impermeable   Half-n-half Clue   5. dangerous or risky.   hazardous   aseptic   concave   feasible   Half-n-half Clue   6. impenetrable or unpassable.   anthropoid   horticultural   impervious   generic   Half-n-half Clue   7. shaped like an oval; ambiguous or baffling.   finite   herbivorous   elliptical   concurrent   Half-n-half Clue