/ ˈfæntəm; NAmE / noun , adjective
■ noun
1.
a ghost :
the phantom of his dead father
2.
a thing that exists only in your imagination
■ adjective [ only before noun ]
1.
like a ghost :
a phantom horseman
2.
existing only in your imagination :
phantom profits
phantom illnesses
a phantom pregnancy (= a condition in which a woman seems to be pregnant but in fact is not)
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WORD ORIGIN
Middle English (also in the sense illusion, delusion ): from Old French fantosme , based on Greek phantasma , from phantazein make visible, from phainein to show.