relief vs relaxation

relief and relaxation both are nouns.

Word	Noun	Adjective	Verb	Adverb
relief	Yes	No	No	No
relaxation	Yes	No	No	No

As nouns, relaxation is a hyponym of relief; that is, relaxation is a word with a more specific, narrower meaning than relief:

relief (noun)	relaxation (noun)
aid for the aged or indigent or handicapped	freedom from activity (work or strain or responsibility)
the act of reducing something unpleasant (as pain or annoyance)	the act of making less strict
assistance in time of difficulty	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 freeing a city or town that has been besieged	an occurrence of control or strength weakening
sculpture consisting of shapes carved on a surface so as to stand out from the surrounding background	a feeling of refreshing tranquility and an absence of tension or worry
a change for the better	(physics) the exponential return of a system to equilibrium after a disturbance
the feeling that comes when something burdensome is removed or reduced	(physiology) the gradual lengthening of inactive muscle or muscle fibers
someone who takes the place of another (as when things get dangerous or difficult)
(law) redress awarded by a court
the condition of being comfortable or relieved (especially after being relieved of distress)
a pause for relaxation