1) - to spit.
2) - a woman whom sleeps around, looks cheap &/or has questionable character.
3) - the waste product of the steel making process.

A slag is a girl that plays around with a guys feelings, leads him on etc, the female version of a fuckboy

1. An individual who cares not for relationships beyond the realm of the sexual, these people sleep with many partners not caring about anything save for the moment of climax.

2. Rubbish that is not worth the time or effort of paying attention to it, but none the less draws one in. Used to describe unpleasent situations.

3. Physical trash, often scrap metals.

4. Drawn from frag, to slag something is to destroy it, used in cases of technological rather then biological items.

1) U.K. criticism: a series of insulting, mocking, or critical comments.

2) USA: To sleep with someone.

Slagging is a term used to describe a kind of harsher form of teasing. While this may seem like an insult to some, to the Irish, it's considered a behavior that shows affection or bonding, and, in some cases, is even used as a compliment.

Usually used in reference to a lady who has a revolving door to her bedroom. Though less common, 'slag' may also be applied to males who spread their seed too thinly and on bad soil.

a woman who has her legs so wide apart she makes the channel tunnel look insignficant