airtight argument

Translations
неопровержимый аргумент
He presented an airtight argument that convinced everyone.
Он представил неопровержимый аргумент, который убедил всех.
Definitions
An airtight argument is a reasoning or line of thought that is so well-structured and logically sound that it cannot be easily refuted or disproven.
Words
airtight

adjective
безупречный
argument

noun
аргумент