The phrase "goes one rocker" refers to an individual who has become mentally unstable or lost touch with reality. There are several synonyms for this phrase, including "goes off the deep end," "loses it," "flips out," "has a meltdown," and "cracks up." These phrases are often used in both casual and formal settings to describe situations where an individual's mental state has deteriorated. It is essential to note that mental health is a sensitive topic and should be handled with care and sensitivity, even when using these phrases in a casual conversation. Asking for professional help and support when needed is crucial in maintaining good mental health.