It is someone, usually from older generations (such as x or baby boomer) who has a set of behaviors rooted from the insecurity of being obsolete or unimportant.
Boomer, in this case, DOES NOT refer to the generation, but to
said personality trait.
Behaviors such as diminishing the potential for
new technologies or shaming those who use it;
Dismissing younger people or behaviors associated with them;
Beating others for
fun;
Attributing problems caused by themselves to younger people or cellphones;
Humiliating, mocking or gaslighting your wife/
husband;
Feeling offended for not being treated as above others, especially minors;
Are all
common behaviors among boomers.