This is Westcountry slang dating back to before the First World War. Skates are very slippery fish and the name was applied to people who had slippery natures in that they were untrustworthy, would try to avoid giving information or were just not very likeable. The use of the name expanded to include people who were wheeler dealers or people who do a lot of ducking and diving but no actual work. The name is disparaging but at the same time may hold just a hint of reluctant admiration. It is, however, a warning as a skate has no conscience and is totally unscrupulous and untrustworthy. The term is believed to have been used extensively by the British armed forces and was used to describe someone who was a slippery customer, fishy and who avoided their share of the work.

Military acronym used as steps to accomplish skating, aka: avoiding work.
S= Seek Cover
K= Keep Quiet
A= Accept No Responsibility
T= Take No Action
E= Evade

street term for ecstasy

Military terminology meaning any service member who avoids his duties.

A scale to weigh drugs.

Its skateboard not rollerblade(fruit booter).

(verb) to leave.