1. reduce expenditure
we need to tighten our belts
This expression means to spend less money than you used to, usually due to a negative change in your financial situation. It tends to be a relatively short term measure which, while it lasts, results in a reduction in your standard of living. While this financial circumstance is often forced upon people, it can also be a choice if you are trying to save up for something, like a holiday, for example. It is common in both social and professional contexts and is similar to the phrase 'pinch pennies' or 'keep to a budget'.