Source : Webster's Revised Unabridged Dictionary (1913)

Frank \Frank\, a. [Compar {Franker}; superl. {Frankest}.] [F.
   franc free, frank, L. Francus a Frank, fr. OHG. Franko the
   name of a Germanic people on the Rhine, who afterward founded
   the French monarchy; cf. AS. franca javelin, Icel. frakka.
   Cf. {Franc}, {French}, a., {Franchise}, n.]
   1. Unbounded by restrictions, limitations, etc.; free. [R.]
      ``It is of frank gift.'' --Spenser.

   2. Free in uttering one's real sentiments; not reserved;
      using no disguise; candid; ingenuous; as, a frank nature,
      conversation, manner, etc.

   3. Liberal; generous; profuse. [Obs.]

            Frank of civilities that cost them nothing.
                                                  --L'Estrange.

   4. Unrestrained; loose; licentious; -- used in a bad sense.
      --Spenser.

   Syn: Ingenuous; candid; artless; plain; open; unreserved;
        undisguised; sincere. See {Candid}, {Ingenuous}.