There is a lot of misinformation here. I will try to correct this.

Simply put, austerity has nothing to do with boosting an economy. The main purpose of austerity is simply as a means to satisfy one's creditors.

Let's say I am a bank and I give a loan to a company. Generally speaking, if you give a loan to someone, you expect to be paid back on a given schedule at a given rate. This is because you also have financial obligations that you need to meet.

Well, it turns out that the company is unable to pay me according to the schedule. At this point, the company is in default. As a creditor, I have two options: work with the company to get them on a pay schedule that both they and I can agree on, or foreclose on them and force them into bankruptcy. Bankruptcy is extremely expensive, time-consuming, and generally something to be avoided except in worst-case scenarios. Thus, I would look to see if I can work out a deal with the company.

Looking into the financials of the company, while the company may be profitable on paper, it might not have the cash flow to pay me back. For instance, they may have a lot of accounts receivable, i.e. they are not collecting money from customers on a timely basis. At the same time, their costs may also be too high-it seems that they have way too many employees given the amount of business they do.

I see a potential for the company to pay me back. If they can increase the money they get from customers, and cut costs by laying off employees, they will generate enough cash to pay me back. In return, I might offer to forgive part of the company's debt, or lower their interest rate, or give them more time to pay me back, and so forth.

That is austerity in a nutshell: the only difference is that one is no longer loaning to a company, but instead to a government.

The differences with a government are that a) you can't really foreclose on a government and b) the government can only increase the money they get by raising taxes. So during government austerity measures, they raise taxes and cut government spending. Both raising taxes and cutting government spending have been fairly well demonstrated to cause short-term economic damage, including unemployment, slow or negative economic growth, to say nothing of general unhappiness in the population. So it is hardly surprising that austerity isn't a good way to boost the economy, because that's not the point.

However: the benefit of austerity is that one can still receive loans from lenders. If a government goes bankrupt, nobody will want to loan them any money. This is a very bad thing. This means that the government will have three choices to raise money for use: raise taxes, cut existing spending, or print money. Unsurprisingly, two of those are things that already come with austerity, and the last one is, if the Weimar Republic hyperinflation and that of many other countries are a good example, a really bad idea.

Yes. I have very little knowledge of economics, but the one that comes to mind is the "Matsukata Deflation" named after Matsukata Masayoshi, the Japanese minister of the treasury from 1885 to 1892. These were policies meant to fight inflation and boost industry.

I'll quote from Volume 5 of the Cambridge History of Japan on the effects:

"In purely economic terms, Matsukata's policies must be judged a success. Nearly bankrupt in 1881, the government increased the ratio of reserves to currency in circulation from 8 percent to 37 percent by 1886; the nation's balance of trade swung from a deficit to surplus; and interest rates declined, all of which encouraged long-term investment in a manufacturing sector with growing capital requirements. On the other hand, what benefited industry hurt agriculture, particularly the small and marginal producers who produced cash crops and had experienced the gains of the previous inflation of prices. The immediate effect of the deflation was to depress commodity prices, thus reducing farm income."