Cash flow is the movement of money in and out of the business.
Profit and cash flow are two very different things. Cash flow is simply about money coming and going from the business. The challenge for managers is to make sure there is always enough cash to pay expenses when they are due, as running out of cash threatens the survival of the business.
If a business runs out of cash and cannot pay its suppliers or workers it is insolvent. The owners must raise extra finance or cease trading. This is why planning ahead and drawing up a cash flow forecast is so important, as it identifies when the firm might need an overdraft.