This is the 1482nd most frequent Chinese word.
未知
Unknown; unknowable.
Here, '未知' is used as a noun meaning 'the unknown', representing things that are not yet known.
未来充满了未知。
The future is full of the unknown.
In this sentence, '未知' refers to aspects of the job that are not yet known or clear, functioning as a descriptor for unclarified things.
她对这份工作的未知产生了兴趣。
She became interested in the unknown aspects of this job.
Here, '未知的领域' refers to 'unknown territories', with '未知' used adjectivally to describe '领域' (territories).