Appropriate vs. Necessary

Difference Between Appropriate and Necessary
Appropriateadjective
Suitable or fit; proper.
The headmaster wondered what an appropriate measure would be to make the pupil behave better.Necessaryadjective
Required, essential, whether logically inescapable or needed in order to achieve a desired result or avoid some penalty.
Although I wished to think that all was false, it was yet necessary that I, who thus thought, must in some sense exist.It is absolutely necessary that you call and confirm your appointment.Appropriateadjective
Suitable to the social situation or to social respect or social discreetness; socially correct; socially discreet; well-mannered; proper.
I don't think it was appropriate for the cashier to tell me out loud in front of all those people at the check-out that my hair-piece looked like it was falling out of place.While it is not considered appropriate for a professor to date his student, there is no such concern once the semester has ended.Necessaryadjective
Unavoidable, inevitable.
If it is absolutely necessary to use public computers, you should plan ahead and forward your e-mail to a temporary, disposable account.Appropriateadjective
(obsolete) Set apart for a particular use or person; reserved.
Necessaryadjective
(obsolete) Determined, involuntary: acting from compulsion rather than free will.
Appropriateverb
To make suitable; to suit.
Necessarynoun
A place to do the "necessary" business of urination and defecation: an outhouse or lavatory.
Appropriateverb
(transitive) To take to oneself; to claim or use, especially as by an exclusive right.
Let no man appropriate the use of a common benefit.Necessarynoun
anything indispensable;
food and shelter are necessities of lifethe essentials of the good lifeallow farmers to buy their requirements under favorable conditionsa place where the requisites of water fuel and fodder can be obtainedAppropriateverb
(transitive) To set apart for, or assign to, a particular person or use, especially in exclusion of all others; with to or for.
A spot of ground is appropriated for a garden.to appropriate money for the increase of the navyNecessaryadjective
absolutely essential
Appropriateverb
To annex (for example a benefice, to a spiritual corporation, as its property).
Necessaryadjective
unavoidably determined by prior circumstances;
the necessary consequences of one's actionsAppropriateverb
give or assign a share of money or time to a particular person or cause;
I will earmark this money for your researchAppropriateverb
take possession of by force, as after an invasion;
the invaders seized the land and property of the inhabitantsThe army seized the townThe militia captured the castleAppropriateadjective
suitable for a particular person or place or condition etc;
a book not appropriate for childrena funeral conducted the appropriate solemnityit seems that an apology is appropriateAppropriateadjective
appropriate for achieving a particular end; implies a lack of concern for fairness
Appropriateadjective
meant or adapted for an occasion or use;
a tractor suitable (or fit) for heavy dutynot an appropriate (or fit) time for flippancyAppropriateadjective
suitable and fitting;
the tailored clothes were harmonious with her military bearingAppropriateadjective
being of striking appropriateness and pertinence;
the successful copywriter is a master of apposite and evocative verbal imagesan apt reply