1. at the utmost : 至多；
2. to the utmost : 极度；
形容词
名词
1. 极度的；最大的
You can use utmost to emphasize the importance or seriousness of something or to emphasize the way that it is done.
2. 极度；极限；最大可能
If you say that you are doing your utmost to do something, you are emphasizing that you are trying as hard as you can to do it.
3. 尽力；极度
If you say that something is done to the utmost, you are emphasizing that it is done to the greatest extent, amount, or degree possible.