effigyyoudaoicibaDictYouDict[effigy 词源字典]
effigy: [16] Effigy comes ultimately from the Latin verb effingere ‘form, portray’. This was a compound formed from the prefix ex- ‘out’ and fingere ‘make, shape’ (source of English faint, feign, fiction, figment, and related to English dairy and dough). It formed the basis of the noun effigiēs ‘representation, likeness, portrait’, which was borrowed into English in the 16th century as effigies: ‘If that you were the good Sir Rowland’s son, as you have whisper’d faithfully you were, and as mine eye doth his effigies witness most truly limn’d and living in your face, be truly welcome hither’, Shakespeare, As you like it 1600.

By the 18th century, however, this had come to be regarded as a plural form, and so a new singular, effigy, was created.
=> dairy, dough, faint, fiction, figment[effigy etymology, effigy origin, 英语词源]
loyalyoudaoicibaDictYouDict
loyal: [16] Loyal, ultimately the same word as legal, has a double history in English. It was originally acquired in the 13th century as leal. This came from Anglo-Norman leal, a descendant of Latin lēgālis ‘legal’. Then in the 16th century it was reborrowed from the modern French form loyal. The semantic link is ‘faithfully carrying out (legal) obligations’.
=> legal
faithful (adj.)youdaoicibaDictYouDict
early 14c., "sincerely religious, devout, pious," especially in reference to Christian practice; mid-14c., "loyal (to a lord, friend, spouse, etc.); true; honest, trustworthy," from faith + -ful. From late 14c. in reference to a tale, a report, etc., "accurate, reliable, true to the facts." The noun sense of "true believer, one who is full of faith" is from late 14c. (Church Latin used fideles in same sense). Related: Faithfully; faithfulness. Old Faithful geyser named 1870 by explorer Gen. Henry Dana Washburn (1832-1871), surveyor-general of the Montana Territory, in reference to the regularity of its outbursts.
unfaithful (adj.)youdaoicibaDictYouDict
mid-14c., "acting falsely," from un- (1) "not" + faithful. In Middle English it also had a sense of "infidel, unbelieving, irreligious" (late 14c.). Sense of "not faithful in marriage" is attested from 1828. Related: Unfaithfully; unfaithfulness.