The DICT Development Group

  tell on
      v 1: give away information about somebody; "He told on his
           classmate who had cheated on the exam" [syn: denounce,
           tell on, betray, give away, rat, grass, shit,
           shop, snitch, stag]
      2: produce an effect or strain on somebody; "Each step told on
         his tired legs"

  39 Moby Thesaurus words for "tell on":
     babble, be indiscreet, be unguarded, bear witness against, betray,
     betray a confidence, blab, blabber, blow the whistle, blurt,
     blurt out, fink, give away, inform, inform against, inform on,
     leak, let drop, let fall, let slip, narc, peach, rat,
     reveal a secret, sell out, sing, snitch, snitch on, spill,
     spill the beans, squeal, stool, talk, tattle, tattle on,
     tell secrets, tell tales, testify against, turn informer