首要

shǒuyào
  1. the most important
  2. of chief importance

CEDICT

Entry Composition

1 首 shǒu
  1. head
  2. chief
  3. first (occasion, thing etc)
  4. classifier for poems, songs etc
2 要 yào
  1. to want; to need; to ask for
  2. will; shall; about to
  3. need to; should
  4. if (same as 要是 yàoshi)
  5. (bound form) important