also flunkey, 1782, Scottish dialect, "footman, liveried servant," of uncertain origin, perhaps a diminutive variant of flanker (in reference to servants running alongside coaches; compare footman). Sense of "flatterer, toady" first recorded 1855. "Recent in literature, but prob. much older in colloquial speech" [Century Dictionary].
flume
flummery
flummox
flung
flunk
flunky
fluonomist
fluor
fluoresce
fluorescence
fluorescent