noun
losing sight of one's goal by indulging in trivial pursuits
A yojijukugo warning against distraction by frivolous hobbies or objects, causing neglect of important aims.
玩物喪志に陥らないよう、日々の目標を見失わないことが大切だ。
It is important not to lose sight of your daily goals so you don't fall into the trap of being distracted by trivial pursuits.
本末転倒 means putting the cart before the horse or mistaking means for ends, while 玩物喪志 specifically warns against being so absorbed in trivial amusements that you forget your serious purpose.
A yojijukugo of Chinese origin, composed of 玩 (play with, trifle with), 物 (thing, object), 喪 (lose, forfeit), and 志 (will, purpose). The exact historical derivation is uncertain, but the phrase is conventionally understood as a warning against losing one's resolve through idle diversions.