, people have two souls
. Really. A child is born with the first, 'standard issue
' soul, so to speak. This is the life
. The second soul enters the body upon its receiving its Jewish name.
Boys are named on the eighth day after birth, at their Bris, ritual circumcision. Girls are named at the reading of the Torah. Some people will wait until Shabbat's torah reading, while others hasten to name their daughters at the soonest Torah reading, which could be on Monday, Thursday or Shabbat.
It is believed that the child's name, while a matter of parental choice, is also a small measure of prophecy, in which the parents will choose a name that best defines their child's specific traits. This second soul enters the child upon naming, and it is the name that is said to give form to and define the child's characteristics.
In a slightly kabbalistic vein, it is interesting to note that in the Bible, it was the Matriarchs (Sarah, Rebecca, Rachel, Leah) who named their children as opposed to the Patriarchs (Abraham, Isaac, and Jacob).
A child's essence is formed from the drop of father's semen, this correlates to the first soul. The child exists, there is a life. Then the embryo spends 9 months forming in the mother's womb, developing hands, feet, fingers, features. This correlates to the second soul.
It is common practice to name children after dead people, however people will not name after people who have died young or gone astray. Part of this is because of the negative associations of the name, and partly because it is the name that lent certain tendencies to the child.
Within Judaism, a person is classified first as being a Jew, on the basis of having descended from the three Patriarchs; Abraham, Isaac, and Jacob. This is the core definition, relating to the first soul. You live - you are a Jew. One is further classified by tribe: one of the twelve sons of Jacob. Your name is _____ - you are a member of this tribe. (This was especially relevant when the Jews lived in Israel with the Temple still standing.)
The unique characteristics to the child were formed within the mother, the naming of a child in some way defined the shape of their soul; in the case of the tribes it was an entire group of people that would have this trait. Hence the Matriarchs (specifically, Rachel and Leah, mothers of the 12 tribes) named their children, defining and further categorizing.
It's likely impossible to say you can know what the name signifies. There are many factors: the meaning of the name, does it translate directly into characteristics? Then there is the person you are named after, and the nuances brought to the name; the first instance of the name ever having been used; name combinations, etc. All factors. Maybe you can guess at it, not much more.
As an aside: it could be coincidence, or imagination, or wanting to believe something desperately, but my mother had two grandfathers. One, B., was a steady, patient sort of man, the other, S., energetic, rash. I have at least 5 cousins named after each, and all the B.'s are solid, dependable kids, good kids. The S.'s are all wild, rambunctious toughies. Good kids too, just of a different sort.
Blockquoted italicized text is very paraphrased and probably slightly skewed from the teachings of the late Lubavitch Rebbe, Menachem Mendel Schneerson.