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fob (v.)[fob 词源字典]: "to cheat," late 14c., from obsolete noun fobbe "cheat, trickster" (late 14c.), which perhaps is from Old French forbeter "to deceive, trick, dupe." Alternative etymology holds that the word is perhaps related to German foppen "to jeer at, make a fool of" (see fop); or from German fuppen, einfuppen "to pocket stealthily," which would connect it to fob (n.).

Meaning "to put or shift off (something) by pretense" is from 1650s; to fob (someone) off "put him off deceitfully" is from 1590s. Related: Fobbed; fobbing.[fob etymology, fob origin, 英语词源]
fop (n.): mid-15c., "foolish person," of unknown origin, perhaps related to obsolete verb fop "make a fool of," from a continental source akin to German foppen "jeer at, make a fool of." Sense of "dandy, coxcomb, man ostentatiously nice in manner and appearance" is from 1670s, perhaps given in derision by those who thought such things foolish. The 18c. was their period of greatest florescense. The junior variety was a fopling (1680s).
His was the sumptuous age of powder and patches. He was especially dainty in the matters of sword-knots, shoe-buckles, and lace ruffles. He was ablaze with jewelry, took snuff with an incomparable air out of a box studded with diamonds, and excelled in the "nice conduct of a clouded cane." [Charles J. Dunphie, "Fops and Foppery," New York, 1876]