unconvincing 

英汉解释

adj. 不足以令人相信的（名词unconvincingness，副词unconvincingly）

同义词

a. improbable，unbelievable，unlikely

反义词

a.   convincing

参考例句

1. What is interesting, however, is the unconvincing nature of his wartime recollections.
不过有趣的是他那让人生疑的战时回忆。
2. "Coming from who-knows-where is the best proof. " Hibari broke the clan-leader's unconvincing retort simply.
“来历不明就是最好的证据。”云雀干脆地打断了自家首领毫无说服力的反驳。
3. Using XPS data is unconvincing, as there could be wide differences between these solution and solid state measurements.
我只知道XPS只能测试固体样，为什么他说了在溶液和固态的测试区别很大？

英英解释

adj.
  1. not convincing
  2. having a probability too low to inspire belief

网络释义

unconvincing
讲不通; 没有说服力的; 不足以令人相信的; 令人不信服;
Unsure unconvincing
没有信心，也不足以令人相信;
unconvincing evidence
无说服力的证据;
The Unconvincing Turtle Titan
神龟巨人;