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4.
Papa Bear's girlfriend. Flier maker for Electronic Assault. All around hot chick who can kick ass and take names when needed. She also has rather large breasts.
Damn, did you see Mama Bear kick that guy's ass? I bet he grabbed her large boobs or something.
by KittehLikesTheMoosic June 16, 2008
 
1.
a mom who can be cuddly and lovable but also has a ferocious side when it's necessary to protect her cubs. can be biological mom, or the head of a group.

can also apply to conflicts within groups, say between siblings or best friends, when the bear steps in for love of both of them.
"Blessings on your new year... your new classes... your interviews...

xoxoxo
Mama Bear"
-direct quote from an email

"Well before you date Anna you have to get approval from mama bear SaraJane"

"I told my mama bear I cried about what they said at school, so she met with the administration and then I transferred"

"Mama bear's give the best hugs"

"Sounds like my siblings are picking on each other again, o wait, there goes mama bear, nevermind"

Love you mama bear! Happy mom day!
by Salvador Mestizo May 08, 2011
 
2.
A tough, aggressive, and protective mother. Often going to extreme lengths to protect her child, usually her son, and herself.
Kid one: 'Wow, that bitch almost beat the shit outta that kid. wtf.'
Kid two: 'Shes the Mama bear.'

Gemme from Sons of Anarchy
by Audrawrr January 14, 2009
 
3.
Adj. Just right.
It's mama bear in here.
by Mr. Mueller November 05, 2010
 
5.
Someone who takes it upon themselves to take care of others while drunk. Often has good intentions, and is the most in control of themselves. However, it is not always appreciated by everybody else. May try to take over drinking games without knowing the rules. Can occasionally be cocky; often just as drunk as those around them but unwilling to admit it or to just give it a rest and submit to the same stupid behavior. Often will lead the group on the drunken walk back home from a party. In extreme cases, may be even drunker than everyone else, but still convinced they are in a position to take care of their friends.
"Why is he trying to carry Elliot?"
"Ahh, he's just being the mama bear again."

"You know what, I don't think you need any more to drink. Why don't you go sit down."
"I'm fine, mama bear. Go play some pong."

"You guys okay back there? Need any help? How we doin'?"
"Damn, let's get home fast so mama bear doesn't have a hernia."
by Nataliza May 11, 2009