Succinct (pronounced suck-sinkt) can be defined as packing a lot of information into relatively few words. The term is highly subjective since, as any teacher will tell you, the presence of information is no guarantee the reader or listener will extract that information. I've often been accused of "over-explaining". Permit me to illustrate with a story.
When my twins were about 6 years old, the oldest (by a whole seven minutes) asked her mother a question about the moon. "Why don't you ask your Papa?", my wife replied, "He likes astronomy." My daughter was silent for a few seconds as I watched from nearby, and she kicked at something imaginary with eyes on her feet. "That's ok", she finally said. "I really didn't want to know that much about it." I took this as a sign that I might need to try to be more succinct with my answers to questions.