officious

First recorded in 1555–65; from Latin officiōsus “obliging, dutiful,” equivalent to offici(um) “service, duty” + -ōsus adjective suffix; see origin at office, -ous

The noun official refers to someone with a certain degree of authority because they were elected or appointed to a position of responsibility within a government, organization, etc. There are White House officials, corporate officials, school board officials, sports officials—the list is seemingly endless. Just keep in mind that the noun official is rather generic and is not used to identify a specific ranking of position or authority as are such titles as president, CEO, treasurer, referee, etc., all of whom could be referred to as officials.
Official can also be an adjective, and that’s when it’s sometimes confused with officious (which is always an adjective). Like many commonly misunderstood words, officious simply looks and sounds as if it could be a synonym for the word it’s confused with—in this case, official.
Given the meaning of official as a noun, it’s not surprising that its adjective senses relate to authority or authorization—for example, “relating to a position of authority” ( the official sovereignty of the queen ); “issued authoritatively” ( waiting for official instructions ); “authorized to act in a designated capacity” ( the project’s official spokesperson ).
Could the adjective officious be that much different? Well, to borrow one of the preceding examples, if you were “waiting for official instructions,” the last thing you’d want is for someone to show up and give you “ officious instructions.” Why? Because officious people rarely have any official authority whatsoever. In fact, what makes them officious is their inclination to be meddlesome and interfering in a self-appointed sort of way. Officious people deliver unsolicited advice, direction, and services regardless of what may or may not be appropriate, and especially without regard for the wishes of those on the receiving end of their “assistance.”
So, if someone shows up to give you officious instructions, by all means wait for the official instructions instead!