To encumber is to make it more difficult for someone or something to do something, to use something or to act or behave normally.
When people are unencumbered, they are free from burdens or responsibilities. Although the origin of the word encumber comes from blocking or obstruction, it is used more often to describe someone who is weighed down or burdened by something. For example, the outcome of the 2010 Climate and Forest Conference in Oslo, showed how some governments are attempting to move forward, and highlighted some of the obstacles that encumber the process of halting deforestation and reducing greenhouse gas emissions.
The related term encumbrance is used in law to refer to a mortgage, claim or other liability attached to a piece of property. After discovering an encumbrance on a property, a potential buyer might try to make a lower offer, decide not to buy the property or to buy the property on the original terms.