uncontrolled mind; wild thoughts
Rare literary noun, almost exclusively found in the idiom 意馬心猿 (いばしんえん), meaning 'uncontrollable passions and wandering thoughts'. Not used in modern conversation.
The four-character idiom 意馬心猿 describes a state where the mind is restless and unsettled.
uncontrollable worldly desires; restless passions
uncontrollable worldly desires; restless passions
From Chinese, literally 'mind horse', referring to thoughts that run wild like an unbridled horse. The exact historical derivation is uncertain.