The Collaborative International Dictionary of English v.0.48:

Droll \Droll\ (dr[=o]l), a. [Compar. Droller; superl.
   Drollest.] [F. dr[^o]le; cf. G. & D. drollig, LG. drullig,
   D. drol a thick and short person, a droll, Sw. troll a
   magical appearance, demon, trolla to use magic arts, enchant,
   Dan. trold elf, imp, Icel. tr["o]ll giant, magician, evil
   spirit, monster. If this is the origin, cf. Trull.]
   Queer, and fitted to provoke laughter; ludicrous from oddity;
   amusing and strange.

   Syn: Comic; comical; farcical; diverting; humorous;
        ridiculous; queer; odd; waggish; facetious; merry;
        laughable; ludicrous. -- Droll, Laughable,
        Comical. Laughable is the generic term, denoting
        anything exciting laughter or worthy of laughter;
        comical denotes something of the kind exhibited in
        comedies, something humorous of the kind exhibited in
        comedies, something, as it were, dramatically humorous;
        droll stands lower on the scale, having reference to
        persons or things which excite laughter by their
        buffoonery or oddity. A laughable incident; a comical
        adventure; a droll story.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Droll \Droll\, n.
   1. One whose practice it is to raise mirth by odd tricks; a
      jester; a buffoon; a merry-andrew. --Prior.
      [1913 Webster]

   2. Something exhibited to raise mirth or sport, as a puppet,
      a farce, and the like.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Droll \Droll\, v. i. [imp. & p. p. Drolled; p. pr. & vb. n.
   Drolling.]
   To jest; to play the buffoon. [R.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Droll \Droll\, v. t.
   1. To lead or influence by jest or trick; to banter or jest;
      to cajole.
      [1913 Webster]

            Men that will not be reasoned into their senses, may
            yet be laughed or drolled into them.  --L'Estrange.
      [1913 Webster]

   2. To make a jest of; to set in a comical light. [R.]
      [1913 Webster]

            This drolling everything is rather fatiguing. -- W.
                                                  D. Howells.
      [1913 Webster]

WordNet (r) 3.0 (2006):

droll
    adj 1: comical in an odd or whimsical manner; "a droll little
           man with a quiet tongue-in-cheek kind of humor"

Moby Thesaurus II by Grady Ward, 1.0:

58 Moby Thesaurus words for "droll":
   Attic, absurd, amusing, biting, bizarre, brilliant, clever,
   comedian, comic, comical, eccentric, facetious, farcical, funny,
   funnyman, hilarious, humorous, humorsome, incongruous, jester,
   jesting, jocose, jocular, joker, jokester, joking, joky, joshing,
   keen, keen-witted, laughable, ludicrous, mordant, nimble-witted,
   pointed, preposterous, priceless, pungent, quaint, quick-witted,
   quipster, quizzical, rapier-like, rich, ridiculous, risible, salt,
   salty, scintillating, screaming, sharp, smart, sparkling,
   sprightly, wag, whimsical, wit, witty