SF flavour is right, it's been used by Anne McCaffrey (in one of the Brain ShipsBrain Ships novels), Larry Niven (Fallen AngelsFallen Angels), Alan Dean Foster (Flinx books), Gordon Dickson (Hokas PokasHokas Pokas), Keith Laumer (OdysseyOdyssey), Doohan & Stirling (The PrivateerThe Privateer), John Ringo (There Will be DragonsThere Will be Dragons) and Poul Anderson (FlandryFlandry) to name but a few.
I imagine it's connected with Shakespeare's "Gentles" (Henry IV & VHenry IV & V, Midsummmer Night's DreamA Midsummmer Night's Dream, Taming of the ShrewTaming of the Shrew) which might be more acceptable to non-fen. ["Fen" is the plural of fan in the speech of SF aficionados.]