Ingenious is an adjective.
Meanings: resourceful; inventive; creative; clever
Ingenuous is an adjective.
Meanings: frank; honest; candid; naïve; innocent
Examples of Ingenious:
1. The architect made an ingenious plan to incorporate a small garden in the terrace area.
2. The athletic coach made ingenious training systems for his wards to ensure fitness.
Examples of Ingenuous:
1. The candidate gave ingenuous answers at the interview.
2. The salesman ingenuously explained the pros and cons of the mobile phone.