adjective. becoming smaller

verb. Present participle of diminish.

noun. A diminishment.

adjective. becoming smaller or less or appearing to do so

"To which I'd add that, to all intents, the term diminishing spare production capacity can be used interchangeably with peak oil."

decreasing  

law of diminishing returns  

finishing  photofinishing  refinishing  

abating  allaying  alleviating  assuaging  blunting  

diminish