Anal Retentive is a not nice way to say that someone is overly pedantic, which is to say they are excessively concerned with minor details or rules. They are overscrupulous. Also, don't use this it is rude and isn't something you'd say to someone.

I don't hear it often, but it isn't unusual either. It is also usually shortened to "anal." (e.g., "Fred is anal about his bookshelf. He has a very specific system and he goes crazy when a single book is even slightly out of order.") It is usually used when someone is very fussy or very focused on small details in a way that annoys the speaker. (If it is something that the speaker likes about the person, they'll use the term "detail-oriented.") It isn't a nice thing to say. I would likely not use it in a business setting. You probably shouldn't use it. If someone says it about you, chances are, they aren't complimenting you.

"Anal retentive" refers to someone who is very detail oriented (as Angela already said). I wouldn't recommend using the phrase. It might sound better to sus something like: Type A personality It has the same meaning and is not offensive. Note: an "Anal retentive" (type A) supervisor can be described as a "micromanager" (which is an okay phrase).