Though officious sounds like official, it means being annoyingly eager to do more than is required. "The officious lunch lady made everyone's food choices her business, and made nasty comments when students chose cookies over carrots."
Officious is a tricky word as it seems like it might mean something like office or official. Instead, it is a word to describe someone that acts more official than they actually are. People who are officious are busybodies. They want to make their opinions known and followed, despite not having any kind of real power.