-f(ə)lē, -li adverb
Etymology: Middle English dredfully, from dredful + -ly
1. : with dread
he looked dreadfully over his shoulder to see if he were followed — Eric Linklater
2. : in such a way as to cause dread : frighteningly
the war whoop ripped dreadfully through the dewy greenness and freshness — Majory S. Douglas
3. : in such a manner or to such a degree as to excite repugnance, pity, disgust, dissatisfaction, or unpleasantness
her response to all her varied experiences strikes the reader as dreadfully deficient in both thought and feeling — A.S.P.Woodhouse
4. : extremely , exceedingly
I'm dreadfully tired, dreadfully stupid, nervy, worked up — Walter de la Mare