atrociousyoudaoicibaDictYouDict[atrocious 词源字典]
atrocious: [17] Traced back to its ultimate source, atrocious meant something not too dissimilar to ‘having a black eye’. Latin āter was ‘black, dark’ (it occurs also in English atrabilious ‘melancholic’ [17] – Greek mélās meant ‘black’), and the stem *-oc-, *-ox meant ‘looking, appearing’ (Latin oculus ‘eye’ and ferox ‘fierce’ – based on ferus ‘wild’, and source of English ferocious – were formed from it, and it goes back to an earlier Indo-European base which also produced Greek ōps ‘eye’ and English eye).

Combined, they formed atrox, literally ‘of a dark or threatening appearance’, hence ‘gloomy, cruel’. English borrowed it (in the stem form atrōci-) originally in the sense ‘wantonly cruel’.
=> eye, ferocious, inoculate, ocular[atrocious etymology, atrocious origin, 英语词源]
dilapidateyoudaoicibaDictYouDict
dilapidate: [16] It is a common misconception that dilapidate means literally ‘fall apart stone by stone’, since the word comes ultimately from Latin lapis ‘stone’ (as in lapis lazuli [14], literally ‘azure stone’). But in fact Latin dīlapidāre meant ‘squander’ (a sense once current in English, but now superseded). It was a compound verb formed from the prefix dis- ‘apart’ and lapidāre ‘throw stones’, and thus originally must have meant literally ‘scatter like stones’, but its only recorded sense is the metaphorical extension ‘throw away or destroy wantonly, squander’.

The application of the word to the destruction of buildings is a piece of later etymologizing.
=> lapis lazuli
slaughter (v.)youdaoicibaDictYouDict
1530s, "butcher an animal for market," from slaughter (n.). Meaning "slay wantonly, ruthlessly, or in great numbers" is from 1580s. Related: Slaughtered; slaughtering.
wanton (adj.)youdaoicibaDictYouDict
early 14c., wan-towen, "resistant to control; willful," from Middle English privative word-forming element wan- "wanting, lacking, deficient," from Old English wan-, which was used interchangeably with un- (1), and is cognate with German wahn- (as in wahnglaube "superstition," wahnschaffen "misshapen," wahnwitzig "mad, foolish"), Dutch wan- (as in wanbestuur "misgovernment," wanluid "discordant sound"), Swedish and Danish van-, from Proto-Germanic *wano- (see wane). Common in Old and Middle English, still present in 18c. glossaries of Scottish and Northern English; this word is its sole modern survival.

Second element is Middle English towen, from Old English togen, past participle of teon "to train, discipline;" literally "to pull, draw," from Proto-Germanic *teuhan (cognates: Old High German ziohan "to pull," from Proto-Germanic *teuhan; see tug (v.)). The basic notion perhaps is "ill-bred, poorly brought up;" compare German ungezogen "ill-bred, rude, naughty," literally "unpulled." Especially of sexual indulgence from late 14c. Meaning "inhumane, merciless" is from 1510s. Related: Wantonly; wantonness.
As Flies to wanton Boyes are we to th' Gods, They kill vs for their sport. [Shakespeare, "Lear," 1605]