This is the 196th most frequent Hebrew word.
בלתי
"בלתי" means "non-" or "un-" (indicating negation).
In this context, "בלתי" is used as a prefix indicating negation, paired with "אפשרית" to mean 'impossible'.
המשימה הזאת בלתי אפשרית לביצוע.
This task is impossible to accomplish.
Here, "בלתי" connects to "מתפשרת" to describe an unyielding manner.
המערכת פועלת בצורה בלתי מתפשרת.
The system operates uncompromisingly.
In this example, "בלתי" when joined with "רגילה" denotes an unusual or extraordinary quality.