A derogatory and offensive slur specifically applicable for a female deemed a "waste of space" by the insulter (male or female). Reasons for the insult can range from the woman's lack of sexual activity or to her failure to be a militant feminist.
Dom: "Are you gonna shag him then"
lilly g-t: "no of course im not going to its just a bit of fun, also women should never have got the vote"
Dom: "you are a serious waste of gash lilly g-t"