elegantyoudaoicibaDictYouDict[elegant 词源字典]
elegant: [15] Someone who made careful, fastidious choices was termed in Latin ēlegāns. This was the present participle of a hypothetical verb *ēlegāre, a derivative of ēligere ‘pick out, select’ (source of English elect). Originally it seems to have been a derogatory term – ‘fussy, foppish’ – but by classical times it signified more approvingly ‘making refined choices’, and was also transferred to the things chosen – ‘choice, tasteful’. English probably acquired the word via French.
=> elect[elegant etymology, elegant origin, 英语词源]
rum (adj.)youdaoicibaDictYouDict
"excellent, fine, good, valuable," 1560s, from rome "fine" (1560s), said to be from Romany rom "male, husband" (see Romany). E.g. rum kicks "Breeches of gold or silver brocade, or richly laced with gold or silver" [Grose, "Dictionary of the Vulgar Tongue," 1785].

A very common 16c. cant word, by 1774 it also had come to mean "odd, strange, bad, spurious," perhaps because it had been so often used approvingly by rogues in reference to one another. This was the main sense after c. 1800.