Discretionary macro funds try to form a view of the state of the world, analyse the implications of this for asset prices and construct a portfolio to take advantage of the situation. For example, a discretionary macro fund may decide to bet that the Euro will fall in value relative to the US dollar and may try to take advantage of that by being short of Euros and long of US dollars. The discretionary part of the description refers to the manager’s ability to make these decisions for the fund themselves.
Multi-Strategy and Diversified Growth funds also fall into this category.