For an adjective that points to the main or most important thing, your best choice is principal. Is your principal goal for the summer to have fun or to earn some extra money?

The word, principal, comes from the Latin principalis "first in importance" and is related to the title of prince. You can see the relation when you think about its meanings — the head of a school, the starring actor in a film, and the client of an agent. Don't confuse principal with its homophone principle, a moral rule or law of nature. If you talk about a country's principal exports, you mean the main ones.

Definitions of principal
  1. adjective
    most important element
    “the principal rivers of America”
    “the principal example”
    synonyms: chief, main, master, primary
    important, of import
    of great significance or value
  2. noun
    the educator who has executive authority for a school
    “she sent unruly pupils to see the principal
    synonyms: head, head teacher, school principal
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    the honorary or titular head of a university
    headmaster, master, schoolmaster
    presiding officer of a school
    a woman headmaster
    teacher in charge of a school boardinghouse
    type of:
    educator, pedagog, pedagogue
    someone who educates young people
  3. noun
    the major party to a financial transaction at a stock exchange; buys and sells for his own account
    synonyms: dealer
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    a financial specialist who trades for his own account and so acts both as a broker and principal
    type of:
    financier, moneyman
    a person skilled in large scale financial transactions
  4. noun
    an actor who plays a principal role
    synonyms: lead, star
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    one of two actors who are given equal status as stars in a play or film
    film star, movie star
    a star who plays leading roles in the cinema
    icon, idol, matinee idol
    someone who is adored blindly and excessively
    TV star, television star
    a star in a television show
    an object of infatuation
    type of:
    actor, histrion, player, role player, thespian
    a theatrical performer
  5. noun
    capital as contrasted with the income derived from it
    synonyms: corpus, principal sum
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    type of:
    wealth in the form of money or property owned by a person or business and human resources of economic value
  6. noun
    the original amount of a debt on which interest is calculated
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    type of:
    money or goods or services owed by one person to another
  7. noun
    (criminal law) any person involved in a criminal offense, regardless of whether the person profits from such involvement
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    criminal, crook, felon, malefactor, outlaw
    someone who has committed a crime or has been legally convicted of a crime
    accessary, accessory
    someone who helps another person commit a crime
    arsonist, firebug, incendiary
    a criminal who illegally sets fire to property
    blackmailer, extortioner, extortionist
    a criminal who extorts money from someone by threatening to expose embarrassing information about them
    bootlegger, moonshiner
    someone who makes or sells illegal liquor
    briber, suborner
    someone who pays (or otherwise incites) you to commit a wrongful act
    coconspirator, conspirator, machinator, plotter
    a member of a conspiracy
    desperado, desperate criminal
    a bold outlaw (especially on the American frontier)
    fugitive, fugitive from justice
    someone who is sought by law officers; someone trying to elude justice
    gangster, mobster
    a criminal who is a member of gang
    a corrupt politician
    highjacker, hijacker
    someone who uses force to take over a vehicle (especially an airplane) in order to reach an alternative destination
    goon, hood, hoodlum, punk, strong-armer, thug, tough, toughie
    an aggressive and violent young criminal
    gaolbird, jail bird, jailbird
    a criminal who has been jailed repeatedly
    abductor, kidnaper, kidnapper, snatcher
    someone who unlawfully seizes and detains a victim (usually for ransom)
    a member of the Mafia crime syndicate in the United States
    gangster's moll, gun moll, moll
    the girlfriend of a gangster
    liquidator, manslayer, murderer
    a criminal who commits homicide (who performs the unlawful premeditated killing of another human being)
    parolee, probationer
    someone released on probation or on parole
    drug dealer, drug peddler, drug trafficker, peddler, pusher
    an unlicensed dealer in illegal drugs
    someone who commits crimes for profit (especially one who obtains money by fraud or extortion)
    raper, rapist
    someone who forces another to have sexual intercourse
    habitual criminal, recidivist, repeater
    someone who is repeatedly arrested for criminal behavior (especially for the same criminal behavior)
    one who habitually ignores the law and does not answer court summonses
    contrabandist, moon curser, moon-curser, runner, smuggler
    someone who imports or exports without paying duties
    stealer, thief
    a criminal who takes property belonging to someone else with the intention of keeping it or selling it
    traitor, treasonist
    someone who betrays his country by committing treason
    law offender, lawbreaker, violator
    someone who violates the law
    type of:
    offender, wrongdoer
    a person who transgresses moral or civil law
Commonly confused words

principal / principle

If offered a choice, would you rather have principles or principals?

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Word Family

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