Another way of saying this is describing someone as "a cradle snatcher" Example: "Look at that old cradle snatcher! His/her partner is 20 years younger than him/her.

"To rob the cradle" is an English expression that means "to date and/or marry someone that is much younger than yourself". How do you define "much younger than yourself"? That answer depends upon the person that you're asking. Person A may think that dating or marrying someone three to five years younger is "robbing the cradle"...much too young for him/her. Person B may feel that an age difference of 10 years or more is too much and too young. Person C may believe that any relationship where there is 30 or more years difference is "robbing the cradle". Each person will have a different view about what "too young" is, as well as who is "robbing the cradle". We call this type of view a "subjective view" (each person has a different view). A good example of this expression can be seen with the American actors Demi Moore and her husband Ashton Kutcher. She is in her 40's and he is in his early 30's. They have been married since 2005 to present. One can correctly use this expression by saying Demi Moore "robbed the cradle" when she married Ashton Kutcher because he is 16 years "her junior "(meaning, younger than she is).

1-To marry with a much younger person. 2- To use a person out of his/her age.