WordNet (r) 3.0 (2006):

poop out
    v 1: use up all one's strength and energy and stop working; "At
         the end of the march, I pooped out" [syn: poop out,
         peter out, run down, run out, conk out]

Moby Thesaurus II by Grady Ward, 1.0:

95 Moby Thesaurus words for "poop out":
   beat, blow, blow up, break, break down, burn out, cave in,
   collapse, come apart, come to naught, come to nothing,
   come unstuck, conk out, crack up, crumble, debilitate, decline,
   disintegrate, do in, do up, droop, drop, enervate, exhaust,
   explode, fade, fag, fag out, fail, fail miserably, faint,
   fall down, fall flat, fall through, fatigue, fizz out, fizzle,
   fizzle out, flag, frazzle, gasp, get bogged down, get hung up,
   get mired, get nowhere, get tired, give out, give way, go downhill,
   go phut, go soft, go to pieces, grow weary, hang up, harass,
   hit the skids, jade, knock out, knock up, languish, misfire,
   overfatigue, overstrain, overtire, overweary, pant, peg out,
   peter out, pine, play out, poop, prostrate, puff, puff and blow,
   run down, run out, sink, succumb, tire, tire out, tire to death,
   tucker, use up, weaken, wear, wear away, wear down, wear on,
   wear out, wear thin, weary, wheeze, wilt, wind, yield