“Above board”

“Cast in stone”

Fixed and impossible to change.

“Fall on deaf ears”

To be ignored or not listened to.

“Cross your mind”

To think of something briefly.

“Cook the books”

To dishonestly change financial records.

“Cut no ice”

To have no effect or influence.

“Across the board”

Affecting everyone or everything.

“Chase rainbows”

To try to achieve something unrealistic.

“Eat your words”

To admit that what you said was wrong.