Merriam-Webster Collegiate Dictionary - relax

 verb  Etymology: Middle English, from Latin ~are, from re- + laxare to loosen, from laxus loose — more at slack  Date: 15th century  transitive verb  1. to make less tense or rigid ; slacken ~ed his grip  2. to make less severe or stringent ; modify ~ immigration laws  3. to deprive of energy, zeal, or strength of purpose  4. to relieve from nervous tension  5. to treat (hair) chemically in order to ~ curls  intransitive verb  1. to become lax, weak, or loose ; rest  2. to become less intense or severe hoped the committee would ~ in its opposition  3. of a muscle or muscle fiber to become inactive and lengthen  4. to cast off social restraint, nervous tension, or anxiety couldn't ~ in crowds  5. to seek rest or recreation ~ at the seashore  6. to relieve constipation  7. to attain equilibrium following the abrupt removal of some influence (as light, high temperature, or stress)  • ~er noun