any tiny, leafy-stemmed, flowerless plant of the class Musci, reproducing by spores and growing in tufts, sods, or mats on moist ground, tree trunks, rocks, etc.

a growth of such plants.

any of various similar plants, as Iceland moss or club moss.

Chiefly Scot. and North England . a swamp or bog.

to cover with a growth of moss

to moss a crumbling wall.

noun

bog , lichen , morass , swamp