The Collaborative International Dictionary of English v.0.48:

Prowler \Prowl"er\, n.
   One that prowls. --Thomson.
   [1913 Webster]

WordNet (r) 3.0 (2006):

prowler
    n 1: someone who prowls or sneaks about; usually with unlawful
         intentions [syn: prowler, sneak, stalker]

Moby Thesaurus II by Grady Ward, 1.0:

32 Moby Thesaurus words for "prowler":
   body snatcher, booster, chicken thief, con man, crook,
   den of thieves, embezzler, filcher, ganef, ghoul, grafter,
   grave robber, jewel thief, land pirate, land shark, land-grabber,
   larcener, larcenist, lifter, peculator, petty thief, pilferer,
   poacher, purloiner, robber, scrounger, shoplifter, sneak thief,
   stealer, swindler, thief, white-collar thief



The Jargon File (version 4.4.7, 29 Dec 2003):

prowler
 n.

    [Unix] A daemon that is run periodically (typically once a week) to seek
    out and erase core files, truncate administrative logfiles, nuke
    lost+found directories, and otherwise clean up the cruft that tends to
    pile up in the corners of a file system. See also reaper, skulker.


The Free On-line Dictionary of Computing (30 December 2018):

prowler
skulker

   (Unix) A daemon that is run periodically (typically once a
   week) to seek out and erase core files, truncate
   administrative logfiles, nuke "lost+found" directories, and
   otherwise clean up the cruft that tends to pile up in the
   corners of a file system.

   See also GFR, reaper, skulker.

   (1995-02-14)