This is the 14976th most frequent Russian word.
подпереть
To prop, support, or brace.
In this sentence, 'подпер' means 'propped' or 'supported against something as a brace.' This usage typically involves the act of placing an object to physically secure or support something else.
Он подпер дверь стулом.
He propped the door with a chair.
Here, 'подпереть' suggests using objects to stabilize or hold open the window. It denotes an action of providing physical support.
Ты можешь подпереть окно книгами.
You can prop the window open with books.
In this context, 'подперли' implies taking preventive measures by providing something to hold or lock the wardrobe in place to prevent falling.