Pedantic means of, relating to, or being a pedant. Pedant is defined as one who makes a show of knowledge, or one who is unimaginative or who unduly emphasizes minutiae in the presentation or use of knowledge.

Another pedantic definition: narrowly, stodgily, and often ostentatiously learned

As used in the sentence:
  1. Professor Sam's lectures were so pedantic that his students sometimes had a hard time understanding the big picture.
  2. The guests were being unnecessarily pedantic by insisting that the husband, and not his wife, should have made the announcement.