Definitions of loosen:

• verb:   become loose or looser or less tight

  Example: "The noose loosened"

• verb:   make loose or looser

  Example: "Loosen the tension on a rope"

• verb:   make less dense

  Example: "Loosen the soil"

• verb:   become less severe or strict
• verb:   make less severe or strict
• verb:   cause to become loose

  Example: "Loosen the necktie"

• verb:   disentangle and raise the fibers of
• name:  A surname (very rare: popularity rank in the U.S.: #55846)