insipid

他的写作风格平淡无味，未能吸引读者。

His writing style is ___insipid and fails to engage the reader.

这杯茶太淡了，几乎没有什么味道。

This cup of tea is so ___insipid that it has almost no flavor.

主旨演讲者的发言乏味无聊，一半的听众都在看手表。

The keynote speaker delivered an ___insipid address that had half the audience checking their watches.