To be at liberty to do something 表示一个人可以自由地、随意地、不受约束地做某事。

例句

Some companies keep information about salaries confidential, and lower-rank managers are not at liberty to discuss them.

This is a free country! I'm at liberty to go wherever I like.

请注意

另一个短语 to take liberties with something 或 someone 的意思是滥用做事的权力，冒昧行事。

Don't take liberties with me, Mr Jones! I am a married woman and the only man allowed to kiss me is my husband.