Ingenious = very intelligent or skillful, inventive, very smart and clever.

• An ingenious person/idea/machine/solution etc.
• The new computer boasts a number of ingenious features.
• He devised an ingenious solution to the problem.
• (noun) ingenuity.

Ingenuous = ( often derog)( of a person or their behaviour) naïve, artless, frank, over-trusting, inexperienced.

• Only the most ingenuous person would believe such a feeble excuse.
• It was rather ingenuous of her to ask a complete stranger to take care of her luggage.
• He seemed too ingenuous for a reporter.
• (noun) ingenuousness.