There is no one definition of "money". M0, M1, M2, M3, MZM are various metrics which have been proposed over time for trying to track the supply of USD all with varying definitions. M2 is frequently used as the simplest and best general case proxy for "how much USD is out in circulation" in a way that tracks credit + currency.

So saying the M2 is high relative to population means that we have been "printing money" (increasing the USD money supply) at a high rate relative to population.