|not transparent or translucent; impenetrable to light; not allowing light to pass through.|
|Without thought or regard.|
|1.||Compare inhibitor a substance that increases the rate of a chemical reaction without itself suffering any permanent chemical change|
|2.||a person or thing that causes a change|
catalyst cat·a·lyst (kāt'l-ĭst)
A substance, usually used in small amounts relative to the reactants, that modifies and increases the rate of a reaction without being consumed in the process.