Ettercap, vixen.
Fechting, fighting.
Feck, quantity, portion.
Feckless, feeble, powerless.
Fell, strong and fiery.
Fey, unlike yourself, strange, as if urged on by fate, or as persons are observed to be in the hour of approaching death or disaster.
Fit, foot.
Flit, to depart.
Flyped, turned up, turned in-side out.
Forbye, in addition to.