Preventative
Pronunciation : Pre*vent"a*tive
Part of Speech : n.
Definition : Defn: That which prevents; -- incorrectly used instead of preventive.
Source : Webster's Unabridged Dictionary, 1913
Merriam-Webster's Everyday Language Reference Set: Includes: The Merriam-Webster Dictionary, The Merriam-Webster Thesaurus, and The Merriam-Webster Vocabulary Builder