1. opening or gap.   catharsis   degradation   conifer   aperture   Hint Half-n-half Clue   2. reservoir or tank for water.   emollient   cipher   cistern   conjecture   Half-n-half Clue   3. decay; breaking into component parts.   immobility   decomposition   emollient   friction   Half-n-half Clue   4. something taken for granted or usurping authority.   dissection   fusion   equilibrium   assumption   Half-n-half Clue   5. lizard noted for changing color to surroundings.   cog   conjecture   chameleon   congruence   Half-n-half Clue   6. collarbone.   apogee   chisel   gyroscope   clavicle   Half-n-half Clue   7. compulsion or repression.   acoustics   constraint   efficacy   asteroid   Half-n-half Clue