ingenuous

John66bessa, you are confusing two different words. Ingenious means "clever, showing great intelligence or insight." It easy to confuse this with ingenuous because of the noun ingenuity, which does not mean the quality of being ingenuous (that's ingenuousness), but the quality of being clever and inventive (and thus is closer in its meaning to "ingenious").

Ingenuous has nothing to do with ingenuity, though as you suggest, it is related to the idea of being "genuine". Ingenuous people are by nature genuine, in that they do not know how to deceive or be other than they are. "Ingenuous" is a close synonym of "naive". Ingenuous people are honest, but not because they choose to be; it is simply their nature to be. They have not yet learned how to dissemble or lie. But worldly people, i.e. people who understand the way world works and who are not ingenuous, may also be genuine: they may be forthright and honest, but in this case, it is a conscious decision.

We say that someone is disingenuous when they pretend to be ingenuous, i.e. they pretend to know less than they actually do, to be more naive than they actually are. They are deceptive, but in the particular way of pretending to be innocent or ignorant of something.

Curiously, the words genius, ingenious, ingenuity, ingenuous, and genuine are all related in that they share the same Latin root -gen- ("relating to birth"), but they are not derived from or based on one another.

This word is based on "genuine," but is convoluted, as are the other words based on "genuine," such as "disingenuous." I feel that "ingenious" means optionally honest. An ingenious person is honest only if he derive some personal benefit from being genuine, such as to gain the confidence of others, and then lies under slightly different circumstances to the same purpose, to reap the benefits of having gained that confidence. http://en.wikiversity.org/wiki/Empathy_Model

I tend to not notice the first "u" and understand ingenious.