Definitions
1.nounA ghost or apparition.
2.nounSomething apparently seen, heard, or sensed, but having no physical reality; an image that appears only in the mind; an illusion or delusion.
3.nounA placeholder for a pair of players when there are an odd number of pairs playing.
4.noun(medical imaging) A test object.
5.adjectiveIllusive.
6.adjectiveFictitious or nonexistent."a phantom limb"