Quiet hiring is when an organization acquires new skills without actually hiring new full-time employees, says Emily Rose McRae, who has led Gartner’s future of work research team since its 2019 inception, focusing on HR practices.

Sometimes, it means hiring short-term contractors. Other times, it means encouraging current employees to temporarily move into new roles within the organization, McRae says.

So...a bullshit meaningless term created to cover a guess.