Sentence:  ... glens hard, full of reptiles; bogs rough, thorny ; woods dark, fiery; roads foul, <WSD>monsterful</WSD>; seas thickened surface-stinking; nails huge, iron; waters dark, unsweet; places (i) abundant, various; an assembly foul, ever-gloomy; winds bitter, wintry; snow frozen, ever-dropping; 
Meaning of the word marked with <WSD> tags:  Characterised by or similar to monsters;