Use quasi when you want to say something is almost but not quite what it describes. A quasi mathematician can add and subtract adequately, but has trouble figuring out fractions.
The adjective quasi is often hyphenated with the word it resembles. Quasi-scientific ideas are ideas that resemble real science, but haven't been backed up with any real evidence. A quasi-religious person may attend church services, but he doesn't take much interest in what's being said. Get the idea? It's a great alternative for "kind of."