Английский Этимологический словарь - derring

-do - originally (1385) dorrying don, lit. "daring to do," from durring "daring," prp. of durren "to dare" + don, inf. of "to do." Misspelled 1500s and mistaken for a noun by Spenser; picked up from him and passed on to Romantic poets as a pseudo-archaism by Sir Walter Scott.