B1
one of five equal parts of something
Dictionary examples:
I spent a fifth of my salary on chocolate. Sweet financial decisions! (0.0)
I read a fifth of the book. The other four-fifths put me to sleep! (0.0)
I finished a fifth of my homework. Four-fifths left to procrastinate on! (0.0)
One fifth is the same as 20 percent. (26.2)