spoof
tough stuff
There are no 5 letter words in the English language that begin with r and end with f.
Aloof Spoof Proof
6 letter f words ending with e:fiddlefacadefaminefeeblefoiblefelineficklefigurefinalefizzlefleecefondleforageforseefutilefreezefringefumble
favor, fever, fiver, furor
filly, fully, fancy, flaky
Some four letter words starting with S and ending with F are:selfserfsurf
Some eight letter words starting with F and ending in E are:favoritefeminineflatlineflexibleforciblefracturefugitive
Flame, frame, flume, flake, fluke, flute.
Of and If
ifag
factual federal flannel foxtail fractal funeral