“Wrap one's head around something”

“Fall on deaf ears”

To be ignored or not listened to.

“Cross your mind”

To think of something briefly.

“Brush up on something”

To improve knowledge or skill by reviewing it.

“Cut no ice”

To have no effect or influence.

“Chase rainbows”

To try to achieve something unrealistic.

“A level head”

Calm and sensible thinking.

“Butter someone up”

To praise someone too much in order to get something.

“Eat your words”

To admit that what you said was wrong.