a.

1. 不切题的，不中肯的[（+to）]
   His impertinent remarks wasted valuable time.

   他那些不着边际的话浪费了宝贵的时间。

2. 不恰当的；不合理的
   impertinent curiosity

   过分的好奇心

3. 傲慢的；不礼貌的；莽撞的
   It was impertinent of him to behave like that.

   他那种举止很不礼貌。

adj.

1. not showing proper respect.
2. formal not pertinent.