mid-14c., "an odor," from O.Fr. flair
"odor or scent," from flairer
"to smell," from L.L. fragrare
"emit (a sweet) odor" (see fragrant
), with shift of -r-
by dissimilation. Sense of "special aptitude" is Amer.Eng. 1925, perhaps from notion of a hound's ability to track scent.