Instadad
A man who marries a person with kids
Example
He really wants to marry Amanda but is worried about his role as an instadad
He's great with kids, he shouldn't worry at all!

Related Slang
Multi-dadding | Having multiple children with different men |
SAHD | Stay-at-home dad |
Dadbod | Male body type with excessive weight in the midsection |
Dad socks | Unfashionable socks often worn by dads |
NASCAR dad | A white, working-class father |
Daddy shaming | Shaming dads for their choices |
An Instadad is a man who marries a person with one or more kids. The man is also commonly referred to as a stepdad.
An instadad often does not have any kids of his own before he weds his bride. But after the marriage he instantly becomes a dad by inheriting whatever churrin belong to his SO. Of course, some instadads already have kids before inheriting more children, like Mike Brady from "The Brady Bunch," a popular example of an instadad. He became a dad to Carol's three daughters when he married her.