ingenious is an adjective, (note the pronunciation "i-ous"), and it's from Latin ingenium, cleverness. It means, clever at inventing; e.g, That's an ingenious idea.Originally Posted by Arunush
ingenuous is also an adjective (note the pronounciation "u-ous"), and it's from Latin ingenuus, frank. It means, artless, frank; e.g., That's an ingenuous response.
ingenue is a noun, and it was borrowed into English from French, so it's pronounced: an'ji'new, wherein 'an' is a nasalized vowel. Ingenue means, an unsophisticated young women, and it's often used to refer to a female who is new at something; i.e., acting.