Q:

What is 'summary execution'?

While reading this blog, I could not find the meaning of 'summary execution'. 
When I tried to find the meaning of this phrase, I got the phrases like 'summary judgement', and 'summary proceeding'. 
My questions are: What is a meaning of 'summary execution'? Is it a legal jargon or an idiomatic phrase as it is written with an inverted comma?

A:

The word summary in your example is not a noun, but an adjective which means: 

Law (Of a judicial process) conducted without the customary legal
  formalities. 

Summary execution means: 

an execution in which a person is accused of a crime and immediately
  killed without benefit of a full and fair trial.

You could find more about summary execution in the Wikipedia article. 
[Oxford Online Dictionary]

