The Collaborative International Dictionary of English v.0.48:

Drizzle \Driz"zle\, v. i. [imp. & p. p. Drizzled; p. pr. & vb.
   n. Drizzling.] [Prop. freq. of AS. dre['o]san to fall. See
   Dreary.]
   To rain slightly in very small drops; to fall, as water from
   the clouds, slowly and in fine particles; as, it drizzles;
   drizzling drops or rain. "Drizzling tears." --Spenser.

   Syn: mizzle, misle.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

drizzling \drizzling\ adj.
   raining lightly in a fine mist.

   Syn: drizzly, misting, misty.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

drizzling
    adj 1: (of rain) falling lightly in very small drops; "a raw
           drizzing rain"