verb

diminish gradually in size, amount, or strength.

traffic has dwindled to a trickle

diminish,decrease,reduce,get smaller,become smaller,grow smaller,become less,grow less,lessen,wane,contract,shrink,fall off,taper off,tail off,drop,fall,go down,sink,slump,plummet,disappear,vanish,die out,nosedive,take a nosedive,decline,degenerate,deteriorate,fail,ebb,slip,slide,go downhill,go to rack and ruin,decay,wither,fade,fade away,peter out,go to pot,go to the dogs,hit the skids,go down the toilet,go down the tubes,go to the pack