traitor

[Chebona~Bula]

Why do people call a traitor 'Blackleg' ?

[Buenchico]

The Oxford English Dictionary has 'origin unknown' so it's up to you whether you choose to believe that it's got something to do with rooks, as suggested here:
http://users.tinyonline.co.uk/gswithenbank/curiousa.htm

Chris

[bernardo]

The version I've heard is that the strikers would kick the strike-breakers on the shins and cause bruises. The same is the origin of the word "scabs".

[Mudman]

I would forget you ever heard that term. You can't go round calling people *****leg anymore.

Look here for example. http://www.theanswerbank.co.uk/News/Question207589.html

[Chebona~Bula]

I'm not going down that road mudman. What a load of ******.