An Asset is any 'thing' a business can own. Buildings, equipment, and vehicles are examples of assets that can be depreciated, while cash, bonds, and inventories are assets that are not depreciated.
Current Assets are most easily converted into cash in less than a year.
Current Liabilities are obligations that must be met within a year.
Inventory is the amount of finished product available for sale. It can be found on the balance sheet in the current assets section.
Liquid Assets are the most current of current assets. Liquid assets can be immediately spent. For example, cash and checks are liquid assets; inventory is a current asset but is not liquid. (Unless it's beer!)
Liquidity is a company's ability to meet current obligations using liquid assets.