Mindfulness is the psychological process of bringing one's attention to experiences occurring in the present moment, which one can develop through the practice of meditation and through other training.
Being mindful means paying close attention to what’s happening in the moment. Put simply, mindfulness is about being present.
Mindfulness can keep you in touch with your goals and hopes.
Practising mindfulness can help you to cope with everyday life and deal with tough times. It can also help you to concentrate, relax and be more productive.
Unfortunately, I don't quite understand the question. Should "mindful" and "mindfulness" form a contrast? Mindfulnes is only the substatement of "mindful". I don't see any difference there. However, several other followers find this question very interesting. You should explain why.
To "mindful" I can say: I am very attentive when I walk on the street or in the forest, because it happens more often now that I stumble over an unevenness and then suddenly fall down, that always gives a few injuries. So I was mindful. And every time even more mindful. But that doesn't prevent me from falling down. On the contrary: the more mindfully I became, the more I fell.
Why? I explain to myself that this kind of mindfulness works like a self-fulfilling prophecy: If you decide that it shouldn't happen, it happens by more. It was only when I stopped worrying about mindfulness and started using walking sticks to support my walking that the problem was solved. I don't want to advise people to do without mindfulness, but only to claim that in order to solve a problem, sometimes the change of the whole situation, for example by a new aid, is more helpful than appealing to one's own mindfulness, which can - negatively - turn into fear of expectation.