what someone is made of

Noun

uncountable

One's personal qualities that project strength, power, courage, or stamina.

Japanese Meaning

その人が持つ内面的な強さや力、勇気、体力といった個性や資質を表す表現

When the competition got tough, he proved what someone is made of.

競争が厳しくなったとき、彼は本当の強さを示した。

Sense（1）

One's personal qualities that project strength, power, courage, or stamina.

You don't have to take it lying down. Show him what you are made of!