peter out

1. Dwindle or diminish and come to an end, as in Their enthusiasm soon petered out. The origin of this usage is unknown, but one authority suggests it may refer to the apostle Peter, whose enthusiastic support of Jesus quickly diminished so that he denied knowing him three times during the night after Jesus's arrest. [Mid-1800s]

Related Words

• abate 
• die out 
• ebb 
• evaporate 
• fade 
• recede 
• tail away www.thesaurus.com
• tail off 
• wane