in-,不，非，support,支撑，承受。即不能承受的，忍耐不住的。

1. Life without Anna had no savour, was tedious, insupportable.

没有安娜的生活毫无情趣，单调乏味，不可忍受。

来自柯林斯例句

2. I can't hold with him — he's insupportable.

我不能容忍他,他简直使人受不了.

来自《简明英汉词典》

3. The heat of this summer is really insupportable.

今年夏天的酷暑实在令人无法忍受.

来自《现代汉英综合大词典》

4. Henry is utterly insupportable.

亨利是一个完全无法相处的人.

来自《现代英汉综合大词典》

5. Too much spending on rearmament would place an insupportable burden on the nation'sproductive capacity.

过于庞大的重整军备开支会给国家的生产力带来难以承受的负担。

来自柯林斯例句