first

alternately, alternatively

alternately, alternatively, either, instead

electively, optionally

desirably, gladly, wishfully

obligingly, voluntarily

ancient, early, primal, primary, prime, primeval, primitive, primordial

antecedent, preceding, previous

distinguished, eminent, illustrious, noble, notable, noteworthy, outstanding, prestigious, signal, star, stellar, superior

high-level, senior, top

important, influential, major, mighty, momentous, significant

incomparable, matchless, unequaled (or unequalled), unparalleled, unsurpassed

celebrated, famed, famous, renowned

high-level, senior

controlling, directing, managing, officiating, overseeing, regnant, reigning, ruling, supervisory

main, major, paramount, predominant, predominate, sovereign (also sovran)

ascendant (also ascendent), dominant, grand, superior, topmost, upmost, upper, uppermost