The Collaborative International Dictionary of English v.0.48:

Laughable \Laugh"a*ble\, a.
   Fitted to excite laughter; as, a laughable story; a laughable
   scene.
   [1913 Webster]

   Syn: Droll; ludicrous; mirthful; comical. See Droll, and
        Ludicrous.
        [1913 Webster] -- Laugh"a*ble*ness, n. --
        Laugh"a*bly, adv.
        [1913 Webster]

WordNet (r) 3.0 (2006):

laughably
    adv 1: so as to arouse or deserve laughter; "her income was
           laughably small, but she managed to live well" [syn:
           laughably, ridiculously, ludicrously,
           preposterously]