简单

简单 (jiǎndān) is the everyday adjective for 'simple' or 'easy.' It describes things that are uncomplicated, plain, or low-effort — a 简单的问题 (simple question), 简单的菜 (a simple dish), 简单的生活 (a simple life). It blurs the line between English 'simple' (few parts) and 'easy' (low difficulty), so Mandarin speakers use it for both.

Two things to know: first, 简单 can describe people as 'naive' or 'uncomplicated' (他这个人很简单), with the connotation shifting between admiration and mild critique by tone; second, the negative form 不简单 ('not simple') is idiomatic praise — 'this kid is 不简单' means 'this kid is remarkable, impressive.' For 'easy' in the sense of a task being effortless, 容易 (róngyì) is the more precise word; 简单 leans toward describing the structure or nature of the thing itself.