Should we use "preventative" or "preventive?"?

I gave this a GQ because it’s something I wonder about often.

Preventive is the older, original word. Preventative is a more recent alternative which seems to be more commonly used as a noun, though it’s also used synonymously with preventive.

Preventive is adjectivial. Preventative is a noun.

One can practice preventive medicine by using a preventative.

I do not think it matters.

@ragingloli Gail is rolling over in her grave. Proper usage of a language always matters.

Well, if we’re speaking of “proper” then preventative is entirely wrong. There’s no specific rule that it’s a noun; I see phrases like “preventative care” and “preventative measures” used all the time. It’s really just an alternate form of “preventive” (that does seem to be used more often as a noun, but not always, and even the noun form is ultimately derived from an adjective) that arose through analogy with words like “affirmative” and “alternative” even though etymologically it doesn’t make sense.

Preventative is a noun and means preventive.
Preventive is an adjective “That prevents or tends to prevent; now, usually, devoted to or concerned with prevention; precautionary; as, preventive measures or medicine. -noun A preventive measure, situation, etc.; specif, Med., a prophylactic.” Copied from Merriam-Webster’s Collegiate Dictionary, 1960 ed.