Sentence:  Steven's cold blood was now heated, and springing from the ground, he rushed forward utterly regardless of science, and with his head down, protected by his bended arm, he closed with a <WSD>swingeing</WSD> right-handed hit that unfortunately caught Ned upon the ear, and sent him reeling, and for the instant half stunned, upon one side. 
Meaning of the word marked with <WSD> tags:  Heavy, powerful, scathing.