Your teacher was probably not very good.
The typical Chinese word for "liberation" is
解放, and it has been used in the same sense of political liberation for many years. Apart from its use in Communist Chinese apparatus (i.e. People's Liberation Army), you also have examples like:
Alternatively, "liberation" can, and has, sometimes been translated using
自由 ("freedom"), depending on the context. Examples include the French newspaper Libération, which has occasionally been translated as
自由人報. Similarly, the video game Assassin's Creed III: Liberation has been translated in Taiwan as
This might be because the word
解放 may be perceived as carrying revolutionary connotations (which some might want to avoid), which is not altogether dissimilar from the situation in English. This works because often the meaning of "liberation" can be expressed as
爭取自由/平等 or equivalent.