To subedit is to go through someone else's writing before it gets published and fix it — spelling, grammar, punctuation, facts, and the shape of the sentences. It is a newspaper and magazine word, mostly British. The person who does this job is a 'sub-editor' (or just a 'sub'), and in Britain that is a real job title at a paper, not a favour a friend does for you. In American English the same job is usually called 'copy editing', and Americans rarely say 'subedit' at all. Notice the two halves of the job: a sub-editor corrects the writing, but also cuts it to fit the space and writes the headline. So it is not only cleaning — it is trimming and packaging too. In everyday talk, people sometimes use it loosely for any careful check of someone's text, and you will hear a teacher say 'I subedited your essay a little', but that is a stretch of the newsroom meaning. It is a normal verb: subedit, subedits, subedited, subediting. You will also see it written 'sub-edit' with a hyphen; both are fine.

審稿、編修（報刊的文字校潤與刪修）