擅自

shànzì
without permission

CEDICT

Entry Composition

1 擅 shàn
  1. without authority
  2. to usurp
  3. to arrogate to oneself
  4. to monopolize
  5. expert in
  6. to be good at
2 自 zì
  1. (bound form) self; oneself
  2. from; since
  3. naturally; as a matter of course