a.

1. 欠考虑的，粗心的，轻率的
2. 不顾及他人的，不为他人着想的
   It was very thoughtless of you to keep her waiting so long.

   你让她等那么久也太不体谅人了。

3. 没有思想的；迟钝的
4. 不考虑的[F][（+of）]
   be thoughtless of danger

   不考虑危险

adj.

1. not showing consideration for other people.
2. without consideration of the consequences.