1.
hitting a ceiling, plateauing, peaking
A state where growth, increase, or improvement has reached its limit and cannot go higher. Used for numbers, performance, prices, and similar metrics.
売上が頭打ちだ。
Sales have plateaued.
人口の増加が頭打ちになっている。
Population growth has hit a ceiling.
この業界は成長が頭打ちで、新しい戦略が必要だ。
Growth in this industry has plateaued, and new strategies are needed.
KEY PATTERN:
頭打ちになる (to plateau, to hit a ceiling) is the most common usage pattern. Also used as a predicate: ～が頭打ちだ.
ETYMOLOGY:
頭 (head) + 打ち (hitting). The image of hitting one's head on a ceiling above, unable to go higher.
USAGE:
Primarily used in business, economics, and data contexts. Common subjects include 売上 (sales), 成長 (growth), 株価 (stock prices), and 人口 (population).