These words are literally meaningless. What does currying or brushing favor have to do with bootlicking, or ingratiating oneself by flattery? The expression shows that a mistake repeated often enough can become standard usage. Favor here is a corruption of Fauvel. Fauvel was a fallow-colored or chestnut horse in the early fourteenth-century satirical poem Roman de Fauvel. The equine hero of this popular French allegory symbolized cunning duplicity; thus cunning people who resorted to insincere flattery to gain someone’s favor were said to curry fauvel, to groom or brush the rascally horse so that he would look kindly on them and perhaps impart to them his powers of duplicity. Fauvel came to be spelled favel in English. But because favel sounded like favor to Englishmen, and because the idea of gaining someone’s favor is the essence of the phrase, the proverbial expression inevitably became to curry favor.