を恥じた

was ashamed of

→ を
phrase Uncommon #9,223
was ashamed of 恥じた is the past form of 恥じる, “to be ashamed of.” The particle を marks what someone is ashamed of.
JA: 彼は自分の間違いを恥じた。
EN: He was ashamed of his mistake.

彼女は自分の不注意を恥じた。

She was ashamed of her carelessness.

彼女は子供の振る舞いを恥じた。

She was ashamed of her child's behavior.

彼はそれまでの自分の努力不足を恥じた。

He was ashamed of not having tried hard enough until then.

トムと話をするごとに、私は自分の無知を恥じた。

Every time I talked to Tom, I felt ashamed of my ignorance.

彼は自分の愚かな間違いを恥じた。

He was ashamed of his stupid mistake.