Google gave me a description:
The word intrapersonal means “within the self”—so, “intrapersonal intelligence” is another term for self-awareness or introspection. It's part of psychologist Howard Gardner's theory of multiple intelligences. People who have high intrapersonal intelligence are aware of their emotions, motivations, beliefs, and goals.
It came from ConnectionsAcademy.com, and it's a nice definition.
Here's my own, from my site, which requires the one above it to make sense.
Interpersonal intelligence is about understanding other people—their non-verbal expressions, their motivations and desires and moods.
Intrapersonal intelligence is understanding one's self in those ways. How are you feeling and why? What are your capabilities and problems and fears and what will help you move toward goals?
The series on multiple intelligences (with links to transcripts of most):
May 5 Visual/spatial intelligence
May 12 Musical intelligence
May 19 Verbal/linguistic intelligence
May 26 Logical/mathematical intelligence
June 2 Interpersonal intelligence (no transcript yet)
June 9 Intrapersonal intelligence
June 16 Bodily/kinesthetic intelligence
June 23 Naturalistic (added as #8)
June 30 Existential / spiritual (in consideration—not fully accepted)
July 7 make-up day (if one of those above has been missed, or a new topic if not)
If you're reading this by e-mail and you need a path to the chatroom, click on the title to get to the blog, which has a tab up to the left with the link and password.