The Collaborative International Dictionary of English v.0.48:

Pilfer \Pil"fer\, v. i. [imp. & p. p. Pilfered; p. pr. & vb.
   n. Pilfering.] [OF. pelfrer. See Pelf.]
   To steal in small quantities, or articles of small value; to
   practice petty theft.
   [1913 Webster]