Why was Gulliver given the title of "SNILPAL" ?

The title "snilpall" is only used once in the text.

Whoever can there bring sufficient proof, that he has strictly observed the laws of his country for seventy-three moons, has a claim to certain privileges, according to his quality or condition of life, with a proportionable sum of money out of a fund appropriated for that use: he likewise acquires the title of snilpall, or legal, which is added to his name, but does not descend to his posterity. And these people thought it a prodigious defect of policy among us, when I told them that our laws were enforced only by penalties, without any mention of reward. It is upon this account that the image of Justice, in their courts of judicature, is formed with six eyes, two before, as many behind, and on each side one, to signify circumspection; with a bag of gold open in her right hand, and a sword sheathed in her left, to show she is more disposed to reward than to punish.