A morass is a tract of soft wet ground, a
marsh or a
bog, and specifically one that is difficult to cross. As a landscape term, it is largely literary now, having been displaced in technical use by
marsh,
fen,
bog, and
mire.
Etymology
It came into English from Dutch in the sixteenth century and behind the Dutch is an Old French word from a Germanic
root meaning
marsh. It’s the same root of
marsh and
mire.