noun
layperson's judgment; amateur opinion
Refers to an opinion or decision made by someone without professional expertise, often implying it may be unreliable or naive.
素人判断で難しい手術を決めるのは危険だ。
Deciding on a difficult surgery based on a layperson's judgment is dangerous.
彼のアドバイスは素人判断だから、専門家に相談したほうがいい。
His advice is just an amateur opinion, so you should consult a specialist.
Compound of 素人 (しろうと, 'amateur, layperson') and 判断 (はんだん, 'judgment, decision').