That's hard to say because intelligence is so hard to define.

由于很难对智能下定义，所以这就变成很难的问题了。

youdao

Why is it so hard to define what Street Photography is about?

为什么定义街头摄影如此困难？

youdao

If the ICC tries too hard to define a word which means so many different things to different people, the consensus it has built up over the unacceptability of certain atrocious deeds could break down.

如果国际刑事法庭花太多精力去定义一个对不同人有不同含义的词汇，那么它所建立的关于不接受某些暴行的共识就会瓦解。

youdao

Who can blame them, when the measure that is used to define safe limits - 'units' - is so hard to understand?

BBC: Alcohol limits advice 'confusing'

Putinism is very hard to define with any degree of precision because the tactics and policies it adopts have varied so greatly depending on the circumstances.

FORBES: Richard Sakwa's Outstanding Analysis of the Putin System's Past, Present, and Future