The examples Willy Ekerslike and Skimble give are actually place names.
The clue seems to be where they got their information from- Historic Place names!!
https://historicplacenames.rcahmw.gov.uk/
To be fair many place names are based on actual words, either as are, or mutated over the centuries (or deriving from the language of an earlier population).
Running 'fferm' through geiriadur.ac.uk
fferm, ffarm, fferem, fferam
[bnth. S. C. ferm(e) ‘farm’]
a Y tir a’r adeiladau, &c., ym meddiant amaethwr neu a ddelir ganddo ar rent, tyddyn; hefyd yn ffig.:
farm, holding; also fig.
b Rhent, treth, toll, taliad:
my orders are to sit here and watch the world go by