Sentence:  In my novella, "Our Lady of Desperation," a painter and civil servant square up to one another. ... One of the protagonists was an artist; so it was assumed I was somehow in his camp. In fact both are <WSD>ratfinks</WSD>; when thieves fall out, honest men, if they don't come into their dues, are at least afforded a wry smile. 
Meaning of the word marked with <WSD> tags:  An informer or spy; a traitor. (from 1960s)