broadside

John Grishamの "The Partner" を読んでいます。 "No, but it's one of the few tactical advantages we can spring on those hyenas circling my carcass. We broadside them with this, and we soften up the sentiment a bit. Think of it, Sandy. The FBI torturing a suspect, an American citizen."
"broadside" の意味が分からないので英英辞書で調べます。
・Oxford English Dictionary: A strongly worded critical attack.: broadsides against political correctness: Atkins' public broadsides against ‘regulatory overreach’ have made him a hero in business and conservative circles
・Cambridge English Dictionary: a strong written or spoken attack (on someone): The candidate fired/launched yet another broadside at the president.
意味は分かりましたが、何故この様な意味になったのか気になったので調べました。Merriam-Websterに書かれていた説明の抜粋です。
In the nautical sense, broadside was originally the entire side of a ship above the water - which is where the guns were placed. The further use of broadside to refer to firing of the guns eventually led to the figurative "volley of abuse" sense.