In toto.—Altogether.
In transitu.—On the passage.
In utrumque paratus.—Prepared for either event.
In vacuo.—In empty space, or in a vacuum.
In vino veritas.—There is truth in wine.
Incognito.—Disguised; unknown.
Index expurgatorius.—A list of prohibited books.
Infra dignitatem.—Beneath one’s dignity.
Innuendo.—Covert meaning; indirect hint.