1. Wraith is a Scottish dialectal word for ghost, spectre, or apparition (WIkipedia). 
2. A fuath, literally meaning "hate" in Scottish Gaelic and Irish Gaelic, designates a class of malevolent mythological spirits.  The "fuath" in collected Gaelic folklore is substituted by the term "kelpie" in the English translation and commentary (Wikipedia).
3. Wraiths and Phantoms are sometimes used interchangeably with these terms as well:  apparition, banshee, incorporeal being, kelpie, etc. (blog by Dr. Lynne Campbell)
   
   

Drawing from the most common parallels between the descriptions of Wraiths (a.k.a. Phantoms), there seems to be more support that they are nasty rather than nice in their disposition and intent.