无日 is a literary adverb with two main uses. The first, often in the pattern 无日不 + verb, means 'every day' or 'no day passes without' — emphasizing that an action happens daily or repeatedly. The second use means 'before long' or 'soon', typically placed at the end of a clause. The pinyin provided here (mó) is a non-standard variant; the common reading is wú rì.