fundamental

/ˌfʌndəˈmɛntl/
adjective
  1. Forming a necessary base or core; of central importance.
    • The fundamental rule of the game is to respect your opponents.
    • Reading and writing are fundamental skills for every student.
    • Understanding gravity is fundamental to studying physics.
  2. Affecting the basic nature of something; essential.
    • There is a fundamental difference between their opinions.
    • The company made a fundamental change to its business model.
    • Access to clean water is a fundamental human right.
Antonyms
noun
  1. A basic principle or essential part of something.
    • The fundamentals of a healthy diet include fruits, vegetables, and whole grains.
    • You need to master the fundamentals before trying advanced techniques.
    • The course teaches the fundamentals of computer programming.