Does anyone help me with my sencond sentence plz? 1.Suddenly the horse jumped up and tipped its rider off. ( tip=tilt, off= from, "tip" n "off" are used in a sense that is very close to their literal meanings. Easy to understand, clear) 2. The police must have been tipped off. (Tip=? , off= ?, which seem to be used in a sense that is way far from their literal meanings. Hard to understand , confusing) Why " tip" + "off" = give someone a secret warning or information ? Thanks for your help in advance.