1 owner, head, chief, leader, chieftain, commander, lord, governor, director, controller, employer, manager, overseer, supervisor, superintendent, taskmaster, slave-driver, principal, sovereign, monarch, ruler, Colloq lord high muck-a-muck, Pooh-Bah, kingpin, big fish, boss, skipper, Brit gaffer, US king-fish, the man, big fish, big boss, bossman; Slang US big cheese, big wheel, Mr Big, chief or head honcho:
He is master of all he surveys. Decisions about punishment are referred to the master
2 expert, authority, genius, craftsman, adept, maestro, mastermind, past master, old hand, virtuoso, ace, professional, Colloq pro, wizard, Chiefly Brit dab hand, US crackerjack; Slang US maven or mavin:
He is a master in the art of chicanery.
3 teacher, tutor, instructor, guide, leader, guru, swami:
She studied under the master for years.
4 adept, ingenious, expert, masterful, masterly, skilful, skilled, proficient:
After twenty years, he became a master craftsman.
5 overall, controlling, principal, main, prime, basic, chief:
Only the leader knows the master plan for conquering the planet. This is the master switch that turns off all the power
6 main, biggest, principal, owner's:
The master bedroom had a bathroom en suite.
7 learn, grasp, become expert in, know inside out and backwards, know, understand:
He claims to have mastered the art of levitation.
8 control, overcome, repress, suppress, subdue, bridle, check, quell, get the better of, Colloq get a grip on:
You must learn to master your emotions.