As yet and Thus far

As yet adverb - Used in negative statement to describe a situation that has existed up to this point or up to the present time.

Thus far is a synonym for as yet in so far topic. In some cases you can use "Thus far" instead an adverb phrase "As yet", when it comes to topics like up until now.

Thus far adverb - Used in negative statement to describe a situation that has existed up to this point or up to the present time.

As yet is a synonym for thus far in up until now topic. You can use "As yet" instead an adverb phrase "Thus far".