dash off

(verb) write quickly. Synonyms: dash off, scratch off, knock off, toss off, fling off. Examples: "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."

(verb) write down hastily. Synonyms: dash down, dash off. Example: "She dashed off a letter to her lawyer."