Primary, Prime Synonyms and Antonyms

Earliest
(Adjective)
Antonyms:
  1. latest
  2. final
Best, principal
(Adjective)
Antonyms:
  1. second-rate
  2. worst
  3. least
  4. inferior
  5. secondary
  6. subordinate
  7. minor
Basic, fundamental
(Adjective)
Antonyms:
  1. secondary
  2. auxiliary
  3. supplemental