be the end of (one)

be the end of (one)

To cause one's ruin, breakdown, downfall, or demise. Often (but not always) used facetiously or lightheartedly. I hate this class, I swear it will be the end of me! My kids are such a handful, sometimes I think they'll be the end of me! If you keep smoking cigarettes, it may well be the end of you.
See also: end, of