Main Entry: fal·la·cy

Pronunciation: \ˈfa-lə-sē\

Function: noun

Inflected Form(s): plural fal·la·cies

Etymology: Latin fallacia, from fallac-, fallax deceitful, from fallere to deceive

Date: 14th century

1 a obsolete : guile, trickery b : deceptive appearance : deception
2 a : a false or mistaken idea <popular fallacies> b : erroneous character : erroneousness
3 : an often plausible argument using false or invalid inference