Dictionary.com/officious (etymology):

officious (uh-FISH-uhs) adjective

1. Marked by excessive eagerness in offering unwanted services or advice to others: an officious host; officious attention.
2. Informal; unofficial.
3. Archaic. Eager to render services or help others.

Source: The American Heritage® Dictionary of the English Language, Fourth Edition
Copyright © 2000 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.

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adj : intrusive in a meddling or offensive manner; “an interfering old woman”; “bustling about self-importantly making an officious nuisance of himself”; “busy about other people's business” [syn: interfering, meddlesome, meddling, busy, busybodied]

Source: WordNet ® 2.0, © 2003 Princeton University

Here is another great word to describe the characters in our stories. I'm sure we know a few officious people in our lives.