1、韜光養晦[詞典]hide one's capacities and bide one's time;
2、[例句]經過十多年的審時度勢,他的性格依然是那麼讓人捉摸不透,韜光養晦高深莫測。After more than a decade of scrutiny, his nature remains enigmatic and his depths not quite fully fathomed.