If you surpass your surplus then you have lots of excess stuff.

過剰 is a relatively formal word that refers to something being excessive. It can also often mean over — like overconsumption, overreaction, or overproduction — in various contexts related to behaviors, emotions, or physical quantities.

This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.