` :The Guardian source uses both terms, and says ``Among the more serious mistakes Figes is accused of making are: Wrongly calling Dina Ioelson-Grodzianskaia [...] a collaborator``. If we're trying to convey the seriousness of this allegation to the reader, who may not know what a trusty is, we should either explain the term, or use the more readily understandable word. I will attempt the former.   `