Meaning of non causa pro causa

non cau•sa pro cau•sa

Pronunciation: (non kô'zu prō kô'zu Lat. nōn kou'sä prō kou'sä), [key]
— Logic. Logic.
  1. the fallacy of giving as a reason for a conclusion a proposition not actually relevant to that conclusion.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.