unrewarding
adj. 不值得做的，无报酬的
反义词
参考例子
1.Defining it is as unrewarding as dissecting a soapbubble.
描述定义它和解剖肥皂泡泡一样吃力不讨好。
2.Such parts are often considered to be thankless, unrewarding.
这种角色通常被认为是吃力不讨好的。
3.Lectures often seem very formal and empty things; recitations generally prove very dull and unrewarding.
课堂讲授常常显得一本正经而空洞无物；背诵往往非常枯燥而收效甚微。
英文解释
adj.
1.not rewarding; not providing personal satisfaction
网络释义
unrewarding
不报答; 不值一做的;
Unrewarding love
恨海情天;