late 12c., "to fear very much, be in shrinking apprehension or expectation of," a shortening of Old English adrædan, contraction of ondrædan "counsel or advise against," also "to dread, fear, be afraid," from ond-, and- "against" (the same first element in answer, from PIE root *ant-) + rædan "to advise" (from PIE root *re- "to reason, count"). Cognate of Old Saxon andradon, Old High German intraten. Related: Dreaded; dreading.
As a noun from c. 1200, "great fear or apprehension; cause or object of apprehension." As a past-participle adjective (from the former strong past participle), "dreaded, frightful," c.1400; later "held in awe" (early 15c.).