Rack one's brains [ji m: o j n m: o zh: and]
new word
Basic explanation
Think about it.
tidy
Lao She's Four Generations under One Family Thirty-seven: "The only way; He is more able to show the appearance of racking his brains; Think for her. "
example sentence
He couldn't think of a solution to this difficult problem.
Approximate antonym
synonym
Try your best to think hard, think hard, think hard.
antonym
Didn't even think about it.