puzzle

PUZZLE noun

[ C ] uk/ˈpʌzl/ us puzzle noun [C]
(SITUATION)

a situation that is very difficult to understand

трудный вопрос, загадка
Scientists have been trying to solve this puzzle for years.
puzzle verb [ T ] uk/ˈpʌzl/ us
to make someone confused because they do not understand something

озадачивать
[ often passive ] I was puzzle d by what he said.
Фразовые глаголы puzzle over sth