A fuath (Scottish Gaelic: fuath; Scottish Gaelic pronunciation: (fuə); lit. ‘hatred'; plural: fuathan; phonetic English: vough, vaugh) is a class of malevolent spirits in Scottish Highland folklore, especially water spirits.

In Sutherland was the so-called Moulin na Vaugha/Fouadh, ‘Mill of the Fuath', haunted by the fuath and her son, the amormphous brollachan. The mill was along a stream off Loch Migdale, and belonged to the Dempster family (Skibo Castle) estate.

A fuath once seen at this mill was a nose-less banshee with yellow hair wearing a green silk dress; in the story of its capture it was tormented into submission by use of steel (awl, and more effectively by a sewing needle), but it turned to a jellyfish-like mass when light was shone on it. A fuath on the estate farm, encountered on a different occasion, had webbed feet.

They sometimes reputedly intermarry with human beings (typically the female), whose offspring have developed a mane and tail.