to force open; to push something open using force.
彼は押し開けたドアの向こうに広い部屋を見つけた。
He found a large room beyond the door he had pushed open.
満員の電車で彼女は腕を使って人混みを押し開けた。
On the crowded train she used her arms to push through the crowd.
古い窓を押し開けて、新鮮な空気を入れた。
She forced open the old window and let in fresh air.