A fork of Rural Dictionary
used by teenage boys to signal if he thinks a female is 'tight'. instead of screaming it out he can guess at how tight she is such as '5p' which means the girl is as tight as a 5 pence piece. if you come across a fat slag then she will probably be a £5 coin, about as big as the palm of your hand.
*tom spots girl* tom: toby!! toby over here!! *toby looks around and clocks the girl* toby: holy shit 5p!! *both laugh*