From Merriam Webster
to recognize, establish or illustrate the worthiness or legitimacy of
How many times have you run across something someone has written and you think WTF are they thinking? You keep reading and you see where they have done something and then to make sure it was justified, they ask everyone in their circle of friends if they were right.
They are seeking *validation* for their actions.
Many people who live this way, want us to know how great their life is. How much money they have, how big their house is, how many friends they have, how great their spousal relationship is, what a great job they have, how much weight they have lost, or how their life is all sunshine and rainbows. All the while, they are trying to build themselves up because in actuality they are more than insecure, they are powerless and have the burning *need* to convince not only themselves but everyone around them just how great they really are.
If these types of people feel they have been *wronged* by someone, they seek to justify their own retaliatory actions by seeking those who would agree with with the course of action that has been taken. They will only ask someone who they know will agree with what they have said or done, thereby giving them the *validation* required to make themselves believe they have done absolutely nothing wrong. This is another way to boost their ego and settle any lingering doubts about their behavior.
Thankfully there are more people who already know their worth, who do not seek to have their life validated.