ConfusableAges 15–20Ingenious or ingenuous
Clever and inventive.
That was an ingenious solution.
Innocent and trusting; open and sincere.
Her ingenuous trust made her easy to fool.
Remember: ingENIous has 'geni', like genius: clever. ingenUOUS has 'genu', like genuine: innocent and open.
Quick check
That was an ____ solution.