deadyoudaoicibaDictYouDict[dead 词源字典]
dead: [OE] Dead is part of a Germanic family of adjectives (including also German tot, Dutch dood, Swedish död, and Gothic dauths) which come from a prehistoric Germanic adjective *dauthaz. This in turn came from an earlier *dhautós, which was the past participle of the verb base that eventually produced English die (thus etymologically dead is in effect a precursor of died). The word’s ultimate source was Indo- European *dheu-, which some have linked with Greek thánatos ‘dead’.
=> die[dead etymology, dead origin, 英语词源]
dead (adj.)youdaoicibaDictYouDict
Old English dead "dead," also "torpid, dull;" of water, "still, standing," from Proto-Germanic *daudaz (cognates: Old Saxon dod, Danish død, Swedish död, Old Frisian dad, Middle Dutch doot, Dutch dood, Old High German tot, German tot, Old Norse dauðr, Gothic dauþs "dead"), from PIE *dhou-toz-, from root *dheu- (3) "to die" (see die (v.)).

Meaning "insensible" is first attested early 13c. Of places, "inactive, dull," from 1580s. Used from 16c. in adjectival sense of "utter, absolute, quite" (as in dead drunk, first attested 1590s; dead heat, 1796). As an adverb, from late 14c. Dead on is 1889, from marksmanship. Dead duck is from 1844. Dead letter is from 1703, used of laws lacking force as well as uncollected mail. Phrase in the dead of the night first recorded 1540s. Dead soldier "emptied liquor bottle" is from 1913 in that form; the image is older.
For but ich haue bote of mi bale I am ded as dorenail (c. 1350).