See also: Your Mom
, ya mum
, Your Mother
, Yo Momma
1. A phrase used often in English youth culture as a generic comeback to an insult of any kind.
2. A response to a question of any sort, often not being in any way related to the person whom is asking's mother or even making any sort of sense, although it can sometimes be fitting and even insulting.
3. Used as part of a larger insult usually following the formula; "Your Mum's so 'x' she is 'y'." This form oftens plays to the target's mother's alledged promiscuity, weight, intellect, age, looks, wealth or background. This is the form of 'Your Mum' used by people with higher (if any) intellect.
Be aware that many people, even if meant as a joke, find the 'Your Mum' insult just that; insulting, even to the point of violence.
The 'Your Mum' insult may appear to be a recent phenomenon, but it has been used by even Shakespeare in his plays, as in Act I Scene 1 of 'Timon of Athens';
Painter: Y'are a dog.
Apemantus: Thy mother's of my generation. What's she, if I be a dog?
The 'Your Mum' insult was also uses in Act IV, Scene II of Titus Andronicus;
Demetrius: Villain, what hast thou done?
Aaron: That which thou canst not undo.
Chiron: Thou hast undone our mother.
Aaron: Villain, I have done thy mother.