Source : Webster's Revised Unabridged Dictionary (1913)

Familiar \Fa*mil`iar\, a. [OE. familer, familier, F. familier,
   fr. L. familiaris, fr. familia family. See {Family}.]
   1. Of or pertaining to a family; domestic. ``Familiar
      feuds.'' --Byron.

   2. Closely acquainted or intimate, as a friend or companion;
      well versed in, as any subject of study; as, familiar with
      the Scriptures.

   3. Characterized by, or exhibiting, the manner of an intimate
      friend; not formal; unconstrained; easy; accessible. ``In
      loose, familiar strains.'' --Addison.

            Be thou familiar, but by no means vulgar. --Shak.

   4. Well known; well understood; common; frequent; as, a
      familiar illustration.

            That war, or peace, or both at once, may be As
            things acquainted and familiar to us. --Shak.

            There is nothing more familiar than this. --Locke.

   5. Improperly acquainted; wrongly intimate. --Camden.

   {Familiar spirit}, a demon or evil spirit supposed to attend
      at call. --1 Sam. xxviii. 3, 7-9.

Familiar \Fa*mil"iar\, n.
   1. An intimate; a companion.

            All my familiars watched for my halting. --Jer. xx.
                                                  10.

   2. An attendant demon or evil spirit. --Shak.

   3. (Court of Inquisition) A confidential officer employed in
      the service of the tribunal, especially in apprehending
      and imprisoning the accused.

Source : WordNet®

familiar
     adj 1: well known or easily recognized; "a familiar figure";
            "familiar songs"; "familiar guests" [ant: {unfamiliar}]
     2: within normal everyday experience; common and ordinary; not
        strange; "familiar ordinary objects found in every home";
        "a familiar everyday scene"; "a familiar excuse"; "a day
        like any other filled with familiar duties and
        experiences" [ant: {strange}]
     3: (usually followed by `with') well informed about or knowing
        thoroughly; "conversant with business trends"; "familiar
        with the complex machinery"; "he was familiar with those
        roads" [syn: {conversant(p)}, {familiar(p)}]
     4: having mutual interests or affections; of established
        friendship; "on familiar terms"; "pretending she is on an
        intimate footing with those she slanders" [syn: {intimate}]

familiar
     n 1: a person attached to the household of a high official (as a
          pope or bishop) who renders service in return for
          support
     2: a person who is frequently in the company of another;
        "drinking companions"; "comrades in arms" [syn: {companion},
         {comrade}, {fellow}, {associate}]
     3: a spirit (usually in animal form) that acts as an assistant
        to a witch or wizard [syn: {familiar spirit}]