However, for the specific case of the "Prudent" man, for the most part, he would almost certainly be the most calculative and observant one.
He may be self-absorbed at times, a proactive contemplative on some occassions, heavily questioning on himself and various aspects of his life when he is alone, and perhaps a little shy on how he reacts. Some negative traits he may possess at first glance are cynicism, jadedness, an untrusting attitude, shy, insecure at times about himself, being unapproachable, pretentiousness, having a passive yet aggressive aura about him, complete disinterest in the people around him or his immediate surroundings and a lack of interest for activity.
Assuming that he seems to be a person who could be approached without harmful repercussions, approaching such a man and to socialize with him, usually requires a great deal of empathy, sometimes in some men - intelligence, honesty and most definitely, a pleasant disposition. Men who are described as such, give high regards to individuals who are able to engage their own thoughts and personal perspectives with constructivity, understanding and mutual respect in conversations. It never hurts to be humble and accepting in such social exchanges with men, and it is always the catalyst that speeds the process of building trust.
Because most men usually bottle up their feelings, they would address their emotions indirectly. And they would keep it a private affair to themselves. There are definitely some emotional issues that we don't want to tell a woman, and we certainly do not want to be labelled as an emotional basketcase by them. Of course, if we are surrounded by people (doesn't matter if they are male or female) whom we trust, and are as emotionally vulnerable just as us, we react with reassurance by knowing that their presence alone does make the decisive difference in our mood and temperament.
When it comes to personal problems and insecurities, our preference to tackle sensitive issues usually is to go at it alone. We may sometimes enlist the help of another male compatriot or friend for advice, but usually choose not to reveal so much of our personal crisis. In events such as this, this is when we are at our most reserved and territorial of our personal space.
The "Prudent" man may not always be an absolute enigma to women, but almost always his reasons for being the way he is are mostly rational, within the reaches of understanding, though it might be subject to unforgiving scrutiny if exposed.
Remember, just because we stay silent, doesn't mean that we do not notice. And chances are, if we do notice someone that catches our attention and become our personal muse (for many reasons), you may be surprised at how "deep the rabbit hole goes".