swear off something
phrasal verb with swear verb uk/sweər/ us/swer/ swore | sworn
发誓不做，保证放弃，下决心戒除
to make a decision to stop doing, using, or being involved with something harmful, such as drugs or alcohol, or something that is not good or helpful
After years of addiction, he swore off drugs completely. 上瘾几年后，他发誓彻底戒毒。