Monkeymind
Mind monkey or monkey mind, from Chinese xinyuan and Sino-Japanese shin'en 心猿, is a Buddhist term meaning "unsettled; restless; capricious; whimsical; fanciful; inconstant; confused; indecisive; uncontrollable". In addition to Buddhist writings, including Chan or Zen, Consciousness-only, Pure Land, and Shingon, this "mind-monkey" psychological metaphor was adopted in Daoism, Neo-Confucianism, poetry, drama, and literature. "Mind-monkey" occurs in two reversible four-character idioms with yima or iba 意馬, most frequently used in Chinese xinyuanyima 心猿意馬 and Japanese ibashin'en 意馬心猿. The "Monkey King" Sun Wukong in the Journey to the West personifies the mind-monkey. Note that much of the following summarizes Carr (1993).
Read more about Monkeymind: Linguistic and Cultural Background, Early Literary History of "mind-monkeys", "Mind-monkey" in English