arch, beyond compare, beyond comparison, cardinal, champion, chief, crowning, distinguished, extraordinary, first, foremost, grand, great, greatest, head, hegemonic, hegemonical, highest, incomparable, inimitable, leading, main, master, matchless, memorable, model, notable, peerless, preeminent, prepollent, prepotent, primary, prime, principal, prominent, regnant, reigning, remarkable, salient, second to none, significant, sovereign, summus, supereminent, superior, superlative, supreme, top, transcendent, transcendental, unapproached, unequaled, unexcelled, unmatched, unparalleled, unrivaled, unsurpassed, without parallel, worthy of notice, worthy of remark
absolute (ideal), best, cardinal (outstanding), central (essential), critical (crucial), dominant, important (significant), influential, leading (ranking first), major, master, material (important), necessary (required), noteworthy, outstanding (prominent), peremptory (imperative), predominant, preferential, prevailing (having superior force), primary, prime (most valuable), principal, professional (stellar), salient, sovereign (absolute), stellar, superior (higher), superlative, vital
Burton's Legal Thesaurus. William C. Burton. 2006
adj.Most important; of highest rank; supreme.
The Essential Law Dictionary. — Sphinx Publishing, An imprint of Sourcebooks, Inc. Amy Hackney Blackwell. 2008.