n. someone who hates another person and tries to attack them or stop them from doing something
Max stole Lee's homework and they've been enemies ever since.

n. the importance or worth of something
What is the value of the prize?

adj. difficult, in a way that tests your ability or determination
It's a challenging book that requires careful reading.

v. to open something
Can you unlock the door for me?

adj. happening at the end of a process
The other team scored twice in the final minute.

v. to give the correct answer or make the correct judgment
I didn't know the answer, so I had to guess.