1. The woman who gave birth to you
2. Attempted insult,or come back, normally from a townie , normally pathetic, normally not very insulting, normally making little or no sense.

Contrary to the above suggestions the term "your mum" is not actually officially an insult. In fact, in many situations it can be seen as a very honourable compliment. For example, if someone calls your mum a "hottie", you can revel in the knowledge that you were first out of all your friends to be in her (provided none of your friends have entered her previous to your birth, might be best to check first). Additionally, your mum might be called "loose" and a "fucking slag" which are street terms for being a good listener.

However, there are certainly usages which can be deemed offensive, as we can see below in the examples. In fact, the British government in the "Your Mum" parliamentary act of 1923 split the term into 5 classes. Use of a level 5 can lead to unlimited fines and/or a prison sentence of 20 years. Community service for a level 4 usage is compulsory, servicing 40+ year old mums to 'keep them fresh'.

(History)

The term was first coined by early Christians after the Bible story in Bernard 3:19 in which Jesus is still a teen and beginning his forages into carpentry and the bush. In the account he is bullied by a gang of locals nicknamed 'The Disciplz', who continually shout abuse and throw pasties at his knees . Eventually, Jesus tires of the pastry-related insults and hits back with his best friend Foreskin, cornering the Disciplz and threatening them with a badger. His tormentors are reluctant to repent until Jesus speaks the most momentous words that possibly the whole world has ever heard...

"Your mothers are all very much like the Romans. They are strong, valiant and innovatice, and they all wear skirts that show their willies."

In the story the Disciplz immediately fall to their knees and pledge allegiance to Jesus, scratching their elbows with shortcake as was the age-old tradition and not leaving his side for 20 more years, even to go to the loo.

Inevitably the usage grew from that point but the term has been somewhat tainted by popular culture and Richard and Judy. We can only pray that those who use it correctly shall be rewarded with the "Second Coming (Of Your Mum)"...

A dorogative statement to do with boning someone parental.

A useless insult used when losing an arguement (see: "can-you-get-out-of-my-library", and "schoolpolicy")

A fat shit that makes the family dog lick peanut butter off of her

A comeback when you can't think of anything to say. A funny term in general.

Someone who has been on top of everyone in yiur city