Preventive is an adjective.

The words are often used interchangeably to denote whatever prevents something else happening or occurring, especially when it is undesirable. However, preventative is often applied to an actual object, especially in noun form, while preventive is mostly reserved for an abstract concept, and remains an adjective: e.g. Preventive medicine regards vitamin C as an effective preventative against colds.

Preventive is an adjective.

They are both valid words.

Preventative is just a modern mis-pronunciation…sort of like Nukular instead of Nuclear…people say it all the time incorrectly, but you still know what they mean.

Some people also say ‘Ideal’ instead of ‘Idea’ or ‘Warsh’ instead of ‘Wash’…LOL