Clueless person. May be spaced out, oblivious. Common sense and/or common courtesy are alien to them. Applies to both someone who is unintentionally/passively irritating, and one who is deliberately so.
It's a silly put-down, so chances are after you use it your anger/annoyance will subside a little.
"You nimnoid, you swiped the last ice cream sandwich! You knew I wanted that!"
Someone cuts you off in traffic. You shout after them, "NIMNOID!"
An obnoxious person finally vacates your personal space. You mutter after them, "nimnoid..."
another term for a station wagon, mini-van, or any other kind of vehicle that is targeted at the "family" demographic(also M.A.V.)
"Tactical advantages aside, the M.A.V. is top of the line for the holy warrior troop transport manufactured by the Church of Latter Day Saints Military Industrial Complex. Also great for family trips...to heathen lands."
12 step recovery jargon referring to someone new who talks about how great life is, now that they'resober. Usually meaning that the person is out of touch with reality.
The new guy seems pretty happy for a dude who has no job, no money and no family. He must be on a pink cloud.