What does Patrick Henry mean by the word "awful" in his speech to the Virginia Convention?

Patrick Henry wanted to raise a militia to prevent the British from taking advantage of them.

In this impassioned speech, Henry’s point was that they could not stand back and let the British walk all over them.  He felt that the way to do this was to raise a militia.  The purpose of his speech was to tell the people that if they did not protect themselves, they would be enslaved to England.

The question...

Patrick Henry wanted to raise a militia to prevent the British from taking advantage of them.

In this impassioned speech, Henry’s point was that they could not stand back and let the British walk all over them.  He felt that the way to do this was to raise a militia.  The purpose of his speech was to tell the people that if they did not protect themselves, they would be enslaved to England.

The question before the House is one of awful moment to this country. For my own part, I consider it as nothing less than a question of freedom or slavery; and in proportion to the magnitude of the subject ought to be the freedom of the debate.

Henry was faced with the problems that many are faced with when trying to get others to act—complacency and fear.  He had to convince the audience that they could not stand back and let themselves be abused by England’s king any more.  By raising a militia, which many colonists considered a treasonous and extreme act, Henry believed they were simply protecting everything they had worked so hard to build.  They were protecting their liberty.

I have but one lamp by which my feet are guided; and that is the lamp of experience. I know of no way of judging of the future but by the past. And judging by the past, I wish to know what there has been in the conduct of the British ministry for the last ten years, to justify those hopes with which gentlemen have been pleased to solace themselves…

Henry ended his speech with the rousing words, "Give me liberty, or give me death!" This seems to have made an impression on the crowd.  It is one thing to fear, but it is quite another to cower.  The resolution was passed.