Very
Very Much, Greatly
adverb
The kanji and the word are exactly the same. That means they share meanings as well.
Since this word is made up of a single kanji, it probably uses the kun'yomi reading. You did not learn this reading, so here's a mnemonic to help you:
When someone starts speaking in very flowery language, you can't help but scoff: "花 — Hah (はなは)!" To you, talking that way feels very pretentious, and you'd prefer if people kept it simple instead of trying to greatly embellish their speech.
そのようなことが事実だとすれば、甚だ遺憾である。
If that sort of thing is true, I'm very sorry.