Synonyms for Principal:

adj.

important (adjective)
major.
master (adjective)
directing, governing, head, senior, master, Presiding, leading, ruling, star, commanding.
most important (adjective)
main, matchless, greatest, key, prime, head, predominant, prominent, incomparable, peerless, premier, transcendent, prevailing, unrivaled, paramount, dominant, chief, primary, supreme, superior, stellar, cardinal, Supereminent, star, major, first, maximum, essential, sovereign, leading, preeminent, mainline, controlling, crowning, capital, foremost, unequaled, highest.

n.

controlling, ultimate, bassist, maximum, busker, mainline, drummer, premier, predominant, matchless, accompanist, stellar, concertmaster, capital, paramount, superior, number one, cellist, transcendent, prime, peerless, preeminent, supreme, dominant, top-ranking, essential, incomparable, composer, ranking, Supereminent, unsurpassed, drum major, sovereign, prevailing, starring, major, highest-ranking, greatest, world-class, bandsman, cardinal, key, highest, front rank, Predominating, fiddler, prominent, second to none, first, unrivaled, unequaled, foremost, crowning. actress, character actor, top, body double, COSTAR, leading lady, double, ham, heart-throb, actor. assignment, attest, alienate, alienation, blind trust, assign, cancel, bail, over, cause, cancellation. elementary, performing arts, basic, protagonist. compound interest, creditor, financier, debt collector, foreclose, extension, creditworthiness, creditworthy, borrowing power, borrowing. bursar, lunch lady, chancellor, guidance counselor, governing body. coach, faculty, housemaster, instructor, headteacher, houseparent, educator. director (noun)
kingpin.
master (noun)
commandant, leader, star, head, squire, landlady, president, landlord, kingpin, headmistress, senior, chief, governor, ruler, proprietress, dean, titleholder, master, commander, abbot, mahatma, mother, quartermaster, director, sire, mandarin, headmaster, proprietor, guru, executive, lord, authority, manager, captain, maestro, officer.
original amount of property either owned or owed (noun)
assets.
person (noun)
star, lead.
person in charge of organization, often an educational one (noun)
director, leader, dean, lead, protagonist, ruler.
principal (noun)
chief, corpus, head, head teacher, star, main, important, principal sum, of import, school principal, dealer, primary, lead.
property (noun)
property, ground, manor, empire, chattel, goods, estate, stock, farm, legacy, inheritance, kingdom, real estate, belongings, possession, assets, title, effects, domain, ranch, realm, fixtures, realty, Resources, holding, wealth, possessions, territory, land.
protagonist (noun)
protagonist.
superior (noun)
superior.

Other synonyms:

actor, lunch lady, premier, cardinal, guidance counselor, governing body, bursar, dominant. chancellor, protagonist, first, predominant, paramount. ultimate. basic. essential
key.
first
foremost.
highest
supreme.
main
main.
pedagogue
educator.
prevalent
prevailing.
principal
prime, capital.
supreme
crowning.
topmost
highest.
Other relevant words:
bursar, COSTAR, protagonist, greatest, busker, corpus, prime, elementary, accompanist, bail, peerless, educator, instructor, actress, controlling, important, unrivaled, headteacher, foremost, extension, incomparable, top-ranking, stellar, attest, key, dominant, creditworthy, lead, sovereign, housemaster, major, concertmaster, essential, top, borrowing, alienate, bandsman, unsurpassed, ham, paramount, ultimate, premier, preeminent, Predominating, number one, supreme, cellist, coach, starring, maximum, first, drummer, prominent, faculty, capital, assign, transcendent, composer, assignment, creditor, dealer, double, crowning, over, cardinal, creditworthiness, unequaled, cause, alienation, primary, basic, financier, bassist, head teacher, chancellor, cancellation, world-class, houseparent, school principal, matchless, actor, prevailing, fiddler, foreclose, predominant, heart-throb, mainline, superior, highest-ranking, Supereminent, commanding, of import, cancel, leading lady, ranking, highest, main, principal sum.