Question: what does it mean when someone says they peaked?
Answer: As a verb, peak (past tense peaked) means “to attain the highest point of activity, development, or popularity,” as in “The artist peaked in the 1980s.” In in the 2000s, we've even taken to using peak as an adjective for a kind of point of saturation, e.g., With so many great shows to watch, I can hardly keep up.