1) The female equivilant of a wasteman, meaning a loser i.e. waste of space.
2) A slut. A female that can be used (shagged) and then promptly discarded. A woman of easy virtue, though not necessarily a prositute.
This phrase comes from the combination of the words wasteman and gash, and is becoming ever more popular in the north london and the home counties of UK.
2)"I linked with a standard wastegash last night. Bare casual ting. You know how we do. "
2- A slutty female which you keep around for sex but whom you have no respect for and can ditch easily.
3- A woman who is attractive when found due to an amount of foundation large enough to build a skyscraper on top of, however the female will likely later found to be quite skanky
A: hey man that chick you were with last friday, you ever get anywhere with her?
B: No man she took her panties off and she had some mad waste-gash
A: dude, that waste-gash you've got back home is starting to smell funny you should get a new one.
B: I hadn't noticed to be honest but i guess you're right. Do you want to go find a new one at the mall?
A: Dude you were totally hitting it up with that chick last night at the club, you tap that?
B: Yeah man but i woke up and she was a total waste-gash.