Impair v. t. : To make worse; to diminish in quantity, value, excellence, or strength; to deteriorate; as, to impair health, character, the mind, value.

Impair v. t. : To grow worse; to deteriorate.

Impair a. : Not fit or appropriate.

Impair n. : Diminution; injury.

Example:
Does eating directly Impair your reasoning abilities while you digest, due to a lack of blood to your brain?

Taxonomy
impair, Merriam-Webster Online Dictionary, Dictionary, webster, Word Games, Webster Online Dictionary with audio pronunciations, Middle English, thesaurus, Vulgar Latin, Late Latin, glossary, language, ESL, Search, transitive verb, Etymology, Anglo-French, Latin.

Defination from the web:
impair from the Merriam-Webster Online Dictionary with audio pronunciations, thesaurus, Word of the Day, and word games. ... worse by or as if by diminishing in some material respect <his health was impaired by overwork> <the strike seriously impaired community services> ...