To Overwhelm
する verb
The pressure used easily collapses whatever it's pushing against. That's why this verb means to overwhelm.
あっとうする
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well. Note that the あつ goes to あっ, as you'd probably expect.
この新しいサイトは他社の日本語学習サイトを圧倒するだろう。
This new site will overwhelm other Japanese language sites.