The Collaborative International Dictionary of English v.0.48:

Piddle \Pid"dle\, v. i. [imp. & p. p. Piddled; p. pr. & vb. n.
   Piddling.] [Cf. dial. Sw. pittla to keep picking at, Sw.
   peta to pick.]
   1. To deal in trifles; to concern one's self with trivial
      matters rather than with those that are important.
      --Ascham.
      [1913 Webster]

   2. To be squeamishly nice about one's food. --Swift.
      [1913 Webster]

   3. To urinate; -- child's word.
      [1913 Webster]

WordNet (r) 3.0 (2006):

piddle
    n 1: liquid excretory product; "there was blood in his urine";
         "the child had to make water" [syn: urine, piss, pee,
         piddle, weewee, water]
    v 1: waste time; spend one's time idly or inefficiently [syn:
         piddle, wanton, wanton away, piddle away, trifle]
    2: eliminate urine; "Again, the cat had made on the expensive
       rug" [syn: make, urinate, piddle, puddle,
       micturate, piss, pee, pee-pee, make water, relieve
       oneself, take a leak, spend a penny, wee, wee-wee,
       pass water]