2 best, foremost, chief; first-rate, first-class, choice, select, superior, pre-eminent, leading, ranking, predominant, unparalleled, matchless, peerless, noteworthy, outstanding, admirable, worthy, exceptional, excellent, extraordinary, exceptional:
She is a prime example of the results of a modern education. Arthur is certainly a prime candidate for the position
3 original, fundamental, basic, elemental, elementary:
The prime cause of scurvy is lack of fresh fruit and vegetables.
4 youth, springtime; best years, heyday, pinnacle, acme, peak, zenith:
Some people reach the prime of life at 60.
5 (make or get) ready, prepare, educate, teach, instruct, coach, train, tutor, drill:
Has Sonia been fully primed to take over the chairmanship when Sir William steps down?
6 inform, advise, notify, apprise, brief:
Having read your book, I am fully primed on American history.