1: A person who is motivated by their ideals. An intra-competitive person often marked by abandoning that which hinders their ideals.
2: One who strives for various degrees of near perfection.
3: Someone that desires more than is needed.
The over-achiever would not get married until she found the perfect father for her future babies. She died alone in her early fifties.
by Nco November 17, 2003
Get a Over Achiever mug for your cousin Nathalie.
A person whose accomplishments seem to exceed their abilities.
In the early 70's, Microsoft was staffed by a motely group of over achievers.
by Kyle Roebuck December 17, 2003
Get a Over Achiever mug for your bunkmate Trump.
A person who is in a relationship with someone who is much better looking than they are.
I am amazed that guy landed a girl like that. He is a total over achiever.
by BMush December 21, 2008
Get a Over Achiever mug for your mate Jovana.
The over-achiever clicked on overachiever even though both spellings are used.
by Nco November 20, 2003
Get a over-achiever mug for your grandma Zora.
Commonly known as: Oac (Pronounced: Oak)
Someone in the military who has yet to see combat and tries too hard to make himself look good in front of superiors, making others look bad.

Typical signs and symptoms of an OAC include, but are not limited to:
- Saying words like, "Hooah", "Squared-Away", "High-speed", "Consolidate", "Water source", "Headgear", "Too easy".
- Being the first to volunteer.
- Having cadences/The Army Song on his iPod.
- Sucking up to leadership.
- Quoting FM's and/or AR's.
*Looking through iPod*
Soldier1: "Why the fuck do you have Army running cadences on your iPod?!"
Over-Achieving Cherry: "'Cause I run to them!"
Soldier2: "Fuckin' OAC!!!"

Over-Achieving Cherry: "I just love jump week, guys.. Jumping is so fun."
Paratrooper1: "WTF? Fuckin' OAC, there's no one here to impress."
by ttwizzler156 February 29, 2012
Get a Over-Achieving Cherry mug for your daughter-in-law Sarah.
Someone who achieves the extra unecessary achievements, but does them in a half-ass fashion.
Patrick decided to be an Over-Under Achiever when he went the extra mile to do his extra credit, even though he already had a 103 percent in his english class. This project was done in a very UNorderly fashion. The rough draft write-up ended up having its title 'rough draft' erased and then replaced with 'Final Project'.
by E-bag March 29, 2010
Get a Over-Under Achiever mug for your daughter-in-law Nathalie.