uncertain

questionable, doubtful, ambiguous, uncertain

这些形容词均含“怀疑的，不确定的”之意。
questionable: 通常指怀疑某行为是否恰当，或指有根有据的怀疑。
doubtful: 指对某个问题持积极怀疑的，有疑问的态度，强调缺乏确信。
ambiguous: 指因缺乏明确感或因为有各种不同的解释而值得怀疑。
uncertain: 多指因缺乏证据或了解而捉摸不定，也指因不能预料而不能作出选择。

形容词 uncertain:

1. lacking or indicating lack of confidence or assurance
   同义词：unsure, incertain
2. not established beyond doubt; still undecided or unknown
3. not established or confirmed
   同义词：unsealed
4. not certain to occur; not inevitable
5. subject to change
   同义词：changeable, unsettled
6. not consistent or dependable
7. ambiguous (especially in the negative)

1. It seems uncertain why he lost the election.
   他落选的原因似乎并不清楚。
2. The company's future is uncertain.
   这家公司前途未卜。
3. I told him in no uncertain terms to mind his own business.
   我直截了当地叫他别管闲事。
4. I told him what I thought of him in no uncertain terms!
   我毫不含糊地把我对他的看法告诉了他。
5. I'm uncertain whether to go or not.
   我不能肯定去还是不去。
6. The uncertain weather delayed our departure.
   天气变换莫测，延误了我们启程。