The phrase "went daffy" is often used to describe someone who has become slightly unhinged or crazy. Synonyms for this phrase include going bonkers, losing one's marbles, going off the deep end, becoming deranged, and going insane. Other synonyms for "went daffy" may include going mental, becoming unbalanced, losing control, and going berserk. These terms often describe someone who has had a sudden change in behavior or personality and may require medical attention or counseling. While the phrase "went daffy" may be used to describe a temporary state of insanity, it is important to seek help if such behavior persists.