Sentence:  Soo whanne sir Laūcelot came thydder / he sawe wryten vpon the tombe letters of gold that said thus / Here shalle come a lybard of kynges blood / and he shalle slee this serpent /.../ Soo thenne sir launcelot lyfte vp the tombe / and there came out an horryble & a <WSD>fyendly</WSD> dragon spyttynge fyre oute of his mouthe<!--Prior quote:Soo whan Sir Launcelot had lyffte up the tombe, there came oute an orryble and a fyendely dragon spyttynge wylde-fyre oute of hys mowthe.--> 
Meaning of the word marked with <WSD> tags:  Like a fiend; devilish.