hammer (something) into (someone or something)
1. To strike something repeatedly, as with a hammer, until it penetrates some surface or thing. Next, you need to hammer these nails into the wall.
2. To commit some piece of information into one's or someone else's long-term memory, especially through intense repetition. How many times do I have to hammer it into your head? Do not drive my car unless I give you permission first! I've just been trying to hammer these formulas into my head for the big test tomorrow!
hammer something into something
and pound something into somethinghammer something in; pound something in Lit. to drive something into something as with a hammer. Todd hammered the spike into the beam. He hammered in the spike. He hammered it in with two hard blows.
hammer into
v.1. To drive something through some surface by striking it with a hammer: The carpenter hammered a nail into the board.
2. To teach or inculcate something to someone by constant, intense repetition: The teacher hammered the multiplication tables into the pupils.