Preventative

Full definition of preventative

Adjective

1. Alternative form of preventive
• 1920, Lillien Jane Martin, Mental hygiene: two years' experience of a clinical psychologist, Warwick &York (1920), p. 78,"That part of mental hygiene which has a prophylactic character falls into two classes, group preventative mental hygiene …"
• 1968, G. Anthony Wedge, N. A. P.: New American Party, Geddes Press Printers (1968), p. 155,"Preventative defense comes in two flavors …"
• 2006, Robert Thompson and Barbara Fritchman Thompson, Repairing & Upgrading Your PC, O'Reilly (2006), p. 70,"The goals of preventative maintenance are to reduce the likelihood of hardware failures, …"

Noun

1. Alternative form of preventive

Usage notes

Preventative is in all senses synonymous with preventive. Many speakers prefer to use preventative in noun senses and preventive in adjective senses.

http://www.wsu.edu/~brians/errors/nonerrors.html#preventive