Ugly
Middle English: from Old Norse uggligr ‘to be dreaded’, from ugga ‘to dread’.
wiktionary
From Middle English ugly, uggely, uglike, borrowed from Old Norse uggligr(“fearful, dreadful, horrible in appearance”), from uggr(“fear, apprehension, dread”) (possibly related to agg(“strife, hate”)), equivalent to ug + -ly. Cognate with Scots ugly, uglie, Icelandic ugglegur. Meaning softened to "very unpleasant to look at" around the late 14th century, and sense of "morally offensive" attested from around 1300.
etymonline
ugly (adj.)
mid-13c., uglike "frightful or horrible in appearance," from a Scandinavian source, such as Old Norse uggligr "dreadful, fearful," from uggr "fear, apprehension, dread" (perhaps related to agg "strife, hate") + -ligr "-like" (see -ly (1)). Meaning softened to "very unpleasant to look at" late 14c. Extended sense of "morally offensive" is attested from c. 1300; that of "ill-tempered" is from 1680s.
Among words for this concept, ugly is unusual in being formed from a root for "fear, dread." More common is a compound meaning "ill-shaped" (such as Greek dyseides, Latin deformis, Irish dochrud, Sanskrit ku-rupa). Another Germanic group has a root sense of "hate, sorrow" (see loath). Ugly duckling (1877) is from the story by Hans Christian Andersen, first translated from Danish to English 1846. Ugly American "U.S. citizen who behaves offensively abroad" is first recorded 1958 as a book title.
