1. not transparent or with no light transmission.   Hint First letter clue   2. corrosive as acid or sarcastic.   First letter clue   3. exact or accurate.   First letter clue   4. evaporating rapidly or highly explosive.   First letter clue   5. pertaining to theory; not practical or applied.   First letter clue   6. at the same time or simultaneous.   First letter clue   7. slanting or indirect.   First letter clue