flex (one's) brainpower

Translations
продемонстрировать (свою) умственную силу
He loves to flex his brainpower during trivia games.
Он любит демонстрировать свою умственную силу во время викторин.
Definitions
To demonstrate or show off one's intelligence, mental abilities, or problem-solving skills, often in a way that is noticeable to others.
Words
flex

verb
демонстрировать
one's

article or possessive pronoun
свой
brainpower

noun
умственные способности