WordNet (r) 3.0 (2006):

dash off
    v 1: write quickly; "She dashed off a note to her husband saying
         she would not be home for supper"; "He scratched off a
         thank-you note to the hostess" [syn: dash off, scratch
         off, knock off, toss off, fling off]
    2: write down hastily; "She dashed off a letter to her lawyer"
       [syn: dash down, dash off]

Moby Thesaurus II by Grady Ward, 1.0:

136 Moby Thesaurus words for "dash off":
   ad-lib, author, bat out, botch, bundle, bungle, bustle, cartoon,
   chalk, charcoal, chase, coauthor, collaborate, color, compose,
   cook up, copy, crayon, crosshatch, crowd, dash, dash on, daub,
   delineate, depict, design, diagram, dig out, do anyhow,
   do by halves, do carelessly, do offhand, doodle, double-time,
   draft, draw, editorialize, extemporize, fake, fake up, festinate,
   formulate, free-lance, fudge up, get going, get moving, ghost,
   ghostwrite, hasten, hasten off, hatch, hurry, hurry away, hurry on,
   hurry through, hurry up, hurry-scurry, hustle, improvisate,
   improvise, indite, jury-rig, knock off, knock out, knock together,
   lash up, leap, light out, limn, lose no time, make haste, make up,
   move quickly, nip, nip off, novelize, paint, paint a picture,
   pamphleteer, patch, patch together, patch up, pencil, picture,
   picturize, play by ear, plunge, portray, post, pound out, prepare,
   press on, produce, push on, race, rough out, roughcast, roughhew,
   run, rush, rush through, scamper, scamper off, scenarize, scramble,
   scrap the plan, scratch, scumble, scurry, scuttle, shade, sketch,
   skin out, slap up, spurt, stencil, strike off, tear, tear off,
   tear out, throw off, throw on paper, throw together, tint,
   toss off, toss out, toss together, trace, trifle with, vamp,
   whip off, whip up, whiz off, whomp up, wing it, write