Words matter. You can't have an intelligent discussion about fiscal policy if you use loaded and misleading words to describe fiscal policy.
Cancelling or postponing a government investment project might be a wise decision. Or it might be a foolish decision. But it is not "austerity".
Implementing or preponing a government investment project might be a wise decision. Or it might be a foolish decision. But it is not "profligacy".
Real economists talk about "tightening" or "loosening" fiscal policy. They don't talk about "austerity" or "profligacy". Not when they are talking among themselves. Or they shouldn't. They don't even talk about "fiscal stimulus", which is another loaded question-begging word.
"Austerity" and "profligacy" are perfectly good words to describe the consumption decisions of a household. But they are bad words to describe the consumption and investment and taxation decisions of a government. Because public finance is not like household finance.
Economists are supposed to understand the difference. So they shouldn't use words that obfuscate the difference.
There is one important exception, where economists should talk about "austerity". And it's an exception that proves the rule.
It would be perfectly correct for economists to say that the UK government in the Second World War had a policy of "austerity". Because the purpose of that policy was to drive down household consumption as low as it could reasonably go. So it would free up as many resources as possible for the war. Yet at the same time the government ran very large deficits. Fiscal policy was extremely "loose". "Austerity" does not mean "tight fiscal policy".
(They implemented austerity by a mixture of: rationing consumer goods; persuading people to save by buying war bonds; and directly controlling the supply-side, so that firms that used to produce consumer goods were told they had to produce weapons instead.)