The Collaborative International Dictionary of English v.0.48:

Police \Po*lice"\, v. t. [imp. & p. p. Policed; p. pr. & vb.
   n. Policing.]
   1. To keep in order by police.
      [1913 Webster]

   2. (Mil.) To make clean; as, to police a camp.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Police \Po*lice"\, n. [F., fr. L. politia the condition of a
   state, government, administration, Gr. ?, fr. ? to be a
   citizen, to govern or administer a state, fr. ? citizen, fr.
   ? city; akin to Skr. pur, puri. Cf. Policy polity,
   Polity.]
   1. A judicial and executive system, for the government of a
      city, town, or district, for the preservation of rights,
      order, cleanliness, health, etc., and for the enforcement
      of the laws and prevention of crime; the administration of
      the laws and regulations of a city, incorporated town, or
      borough.
      [1913 Webster]

   2. That which concerns the order of the community; the
      internal regulation of a state.
      [1913 Webster]

   3. The organized body of civil officers in a city, town, or
      district, whose particular duties are the preservation of
      good order, the prevention and detection of crime, and the
      enforcement of the laws.
      [1913 Webster]

   4. (Mil.) Military police, the body of soldiers detailed to
      preserve civil order and attend to sanitary arrangements
      in a camp or garrison.
      [1913 Webster]

   5. The cleaning of a camp or garrison, or the state ? a camp
      as to cleanliness.
      [1913 Webster]

   Police commissioner, a civil officer, usually one of a
      board, commissioned to regulate and control the
      appointment, duties, and discipline of the police.

   Police constable, or Police officer, a policeman.

   Police court, a minor court to try persons brought before
      it by the police.

   Police inspector, an officer of police ranking next below a
      superintendent.

   Police jury, a body of officers who collectively exercise
      jurisdiction in certain cases of police, as levying taxes,
      etc.; -- so called in Louisiana. --Bouvier.

   Police justice, or Police magistrate, a judge of a police
      court.

   Police offenses (Law), minor offenses against the order of
      the community, of which a police court may have final
      jurisdiction.

   Police station, the headquarters of the police, or of a
      section of them; the place where the police assemble for
      orders, and to which they take arrested persons.
      [1913 Webster]

WordNet (r) 3.0 (2006):

police
    n 1: the force of policemen and officers; "the law came looking
         for him" [syn: police, police force, constabulary,
         law]
    v 1: maintain the security of by carrying out a patrol [syn:
         patrol, police]

Moby Thesaurus II by Grady Ward, 1.0:

107 Moby Thesaurus words for "police":
   Cheka, FBI, Gestapo, Interpol, MP, MVD, Mounties, NKVD, OGPU, RCMP,
   SP, Scotland Yard, administer, arm, armor, bless, bull, champion,
   clean up, clear the decks, clear up, cloak, compass about,
   constabulary, control, cop, copper, copyright, county police,
   cover, cushion, defend, enforce, ensure, fence, fend, fix up, fuzz,
   groom, guarantee, guard, harbor, haven, heat, highway patrol,
   insure, keep, keep from harm, keep guard, keep vigil, keep watch,
   law enforcement agency, make safe, man, military police, monitor,
   mount guard, neaten, nestle, observe, officer, oversee, patent,
   patrol, peace officer, police force, police officer, police up,
   political police, posse, protect, provincial police, put in trim,
   register, regulate, ride shotgun for, riot police, safeguard,
   screen, secret police, secure, security force, shelter, shield,
   shore patrol, shroud, special police, spruce, spruce up,
   stand guard, stand sentinel, state police, straighten up,
   supervise, tactical police, the cops, the fuzz, tidy, tidy up,
   trig up, trim, trim up, troopers, underwrite, vigilance committee,
   vigilantes, watch



The Devil's Dictionary (1881-1906):

POLICE, n.  An armed force for protection and participation.