if you say you will do something come hell or high water, you mean you are determined to do it even if it is difficult.

I'll get you to the airport by 12 o'clock, come hell or high water.

• turn something topsy-turvy
• turn something upside down
• turn swords into ploughshares
• turn tail
• turn the clock back
• turn the corner
• turn the knife
• turn the other cheek
• turn the page
• turn the screws on
• turn the screws on someone
• turn the tables
• turn the tables on
• turn the tables on someone
• turn the tables on something
• turn the tide
• turn to
• turn to good account
• turn topsy-turvy
• turn to someone
• turn to something
• turn turtle
• turn up
• turn up like a bad penny
• turn upside down