This is the 12648th most frequent Turkish word.
imkânsız
Impossible.
Here, 'imkânsız' is used as an adjective describing the task of completing the job in a short time, highlighting its improbability.
Bu kadar kısa sürede bu işi tamamlamak imkânsız.
Finishing this job in such a short time is impossible.
In this sentence, 'imkânsız' functions as a noun, referring to the state of being impossible or unfeasible.
Ona imkânsız olduğunu söyledim ama yine de denemek istedi.
I told her that it was impossible, but she still wanted to try.
Here, 'imkânsız' is used to denote the concept of impossibility, negated to emphasize the difficulty but feasibility of achieving a perfect score.