例文（１級）：renegate，stultify

He is a renegade who has renounced his former beliefs and joined the
opposing side, but his actions only serve to stultify the cause he
claims to support.
(彼は、かつての信念を放棄し、反対派に加わった裏切り者ですが、彼の行動は彼が支持する理由を退屈させるだけです。)

renegate： 裏切り者、背教者
stultify： を退屈させる