"to hide, conceal," early 14c., a Northern English and Northern Midlands word, from Old Norse fela "to hide," from PRoto-Germanic *felhan (Cognates: Gothic filhan "to hide, bury," Old English feolan "enter, penetrate, pass into").

"faithful," 1560s, not found in Middle English but apparently from Old French feal "faithful, loyal, true, sincere," collateral form of feeil, from Latin fidelis "loyal" (see fidelity).