significant名词是significance

significant

adj.有重大意义的;显著的;有某种意义的;别有含义的;意味深长的

There remained one significant problem.

还有一个非常重要的问题。

The navy played a limited but significant role in defeating the rebellion

海军在平息这场叛乱的过程中起到了有限但却十分重要的作用。

There are no significant differences between the two groups of students.

这两组学生没有明显差别。