spoil (one) rotten(redirected from spoiling rotten)
spoil (one) rotten
To cause one to expect to receive everything they want by always giving it to them. In this phrase, "rotten" is an intensifier. I think some grandparents believe it's their duty to spoil their grandchildren rotten.
Fig. indulged in; greatly spoiled. This kid is spoiled rotten! I was spoiled rotten when I was a child, so I'm used to this kind of wasteful luxury.