To catch someone in one's arms (for example to prevent a fall) or to hold someone back physically; to stop someone by embracing them.
電車の中で彼女はよろめいた男性を素早く抱きとめた。
On the train she quickly caught a man who had staggered.
彼はドアを開けようとする妻の腕を抱きとめて、話を続けた。
He held his wife's arm to stop her leaving the room and continued talking.
子供が転びそうになったので、慌てて抱きとめた。
The child was about to fall, so I hurriedly caught them.