relaxation - noun

(physiology) the gradual lengthening of inactive muscle or muscle fibers

(physics) the exponential return of a system to equilibrium after a disturbance

a feeling of refreshing tranquility and an absence of tension or worry

an occurrence of control or strength weakening

freedom from activity (work or strain or responsibility)

a method of solving simultaneous equations by guessing a solution and then reducing the errors that result by successive approximations until all the errors are less than some specified amount

the act of making less strict

relaxation - thesaurus

ease   easiness   liberalisation   liberalization   loosening   repose   rest   slackening