a : accumulated philosophic or scientific learning : knowledge
b : ability to discern inner qualities and relationships : insight
c : good sense : judgment
d : generally accepted belief <challenges what has become accepted wisdom among many historians — Robert Darnton>
: a wise attitude, belief, or course of action
: the teachings of the ancient wise men
wisdom (countable and uncountable; plural wisdoms)
- (uncountable) An element of personal character that enables one to distinguish the wise from the unwise.
- (countable) A piece of wise advice.
- The discretionary use of knowledge for the greatest good.
- The ability to apply relevant knowledge in an insightful way, especially to different situations from that in which the knowledge was gained.
- The ability to make a decision based on the combination of knowledge, experience, and intuitive understanding.
- (theology) The ability to know and apply spiritual truths.
Wisdom is knowing what you know as well as what you dont know.
Wisdom is not not simply knowing what to do, but doing it.
Many people will without invitation offer their "words of wisdom", wise people realise when it is not their time or place to do so.
A wise person does not think less of another who chooses not to follow their advice.
Wisdom is not undermining a person for their weaknesses, but appreciating their strengths differ from yours.
Webster, usually terse, is almost monosyllabic on this one. It asks us to choose between either knowledge (see the etymology), insight and judgement. Wiktionary, after making the correct references to "wise", certainly gives us something to think about. I think Wiktionary's offering #5 may be the most revealing. UD fails to supply a definition in the conventional sense at all. Indeed none of the other attempts (further down the same page: "wisdom" - UD) does any better.
I'm going straight to Doug; "wisdom" is formed from "wise", so here's what he has to say about "wise":
O.E. wis, from P.Gmc. *wisaz (cf. O.S., O.Fris. wis, O.N. viss, Du. wijs, Ger. weise "wise"), from pp. adj. *wittos of PIE base *weid- "to see," hence "to know" (see vision). Slang meaning "aware, cunning" first attested 1896. Related to the source of O.E. witan "to know, wit."
A wise man has no extensive knowledge; He who has extensive knowledge is not a wise man. [Lao-tzu, "Tao te Ching," c.550 B.C.E.]
Wise guy is attested from 1896, Amer.Eng. Wisenheimer, with mock German or Yiddish surname suffix, first recorded 1904.
As you can see, the etymology offers little help. Wise comes from the same Proto-Indo-European root as vision, and just means "knowing stuff". Doug's inclusion of a quotation from the Tao shows that he too is aware of some mystery, or at the very least, mystification of the idea of "wisdom".
It is my contention that we all observe, both in others and in ourselves, the occasional evidence of good or insightful judgement, in the absense, or at the very least paucity, of prior or learned knowledge. There seem to be situations and problems that we can deal with without recourse to trained intelligence. We call those who are able to do this wise. We observe that wisdom is more often found in older people, even though it evidently isn't an inevitable consequence of ageing. So we conclude that some people, through experience, become more wise over time.
I suggest that a great deal of what wisdom is has to do with the experience of being human, and being social. Much of what we call wisdom has to do with understanding other people and understanding how people behave as individuals and as groups. With this understanding comes the knowledge of how to handle difficult social situations, an, especially, how to pass-on both knowledge and wisdom to others.
When you describe (or even just think of) one of your characters as "wise", not only are you opening yourself up to a slew of highly subjective challenges ("you said that guy was wise; what he just did doesn't seem very wise to me."), but also obliging the reader to wonder what you meant by wise, yourself. This is, IMO, one of those cases where you need to show what the character says, and/or does and/or thinks, and let the reader come up with the description "wise" on his own.
Feel free to comment with your definitions of wise without copy/pasting from an online dictionary that I didn't use!
Or go back to the first post in this series.