1. pertaining to the stars or spiritual.   astral   concurrent   humid   aromatic   Hint Half-n-half Clue   2. theoretical and not concrete.   buoyant   immune   elliptical   abstract   Half-n-half Clue   3. pertaining to the art of gardening.   cognitive   horticultural   determinate   fundamental   Half-n-half Clue   4. heat-liberating.   herbivorous   calorific   cerebral   ebullient   Half-n-half Clue   5. periodic shedding (of leaves).   igneous   integral   combustible   deciduous   Half-n-half Clue   6. herb-eating or vegetarian.   discrete   herbivorous   hypothetical   centrifugal   Half-n-half Clue   7. breakable or fragile.   dynamic   cerebral   brittle   eccentric   Half-n-half Clue