Translation

自分に禁じる / 自制して断つ / 自己放棄する

Meaning

Abnegate means to deny yourself something you want, or to put aside your own interests, often for duty, discipline, or principle. It is formal and serious, not a normal word for simply refusing an offer.

Examples

• 彼女は研究を続けるために多くの楽しみを自分に禁じた。
  She abnegated many pleasures to continue her research.
• その修道士は個人的な欲望を断つ生活を選んだ。
  The monk chose to abnegate personal desire.