a pun. KGB is pronounced "KaGeBe" or "KeGeBe". The last sounds [eb] form the root of the ef-verb. "ebun" means "effer" in Russian, Thus, "kegebun" is a compound word [noun] with two roots [there are many such words in German and in Russian], meaning, literally, "KGB-effer". That's how we used to refer to them. Derivative adjective "kegebuchij" [with varying endings per gender, number and case] means "KGB-effing". For example, "our resident kegebun posters again pour forth their kegebuchij garbage".
Very interesting, thanks for the clarification.
Meanwhile, tell me how to pronounce the name "Gaidar". Please tell me it's not pronounced "GAY-DAR"...