Ah , you're not English! ~ a 'post-fix , is like a 'prefix' , only it comes after the word . . . . like pretty . . . . lucky ; pretty . . . . pleased ; pretty . . . . vacant .
“you’re not english” considering i’m born & bred in england i think i am mate. just what you said doesn’t make sense at all.
+2 answers in: “If you are 'pretty' , what post-fix would follow?”