精通

jīngtōng
  1. to be proficient in
  2. to master (a subject)

CEDICT

Entry Composition

1 精 jīng
  1. essence
  2. extract
  3. vitality
  4. energy
  5. semen
  6. sperm
  7. mythical goblin spirit
  8. highly perfected
  9. elite
  10. the pick of sth
  11. proficient (refined ability)
  12. extremely (fine)
  13. selected rice (archaic)
2 通 tōng
  1. to go through
  2. to know well
  3. (suffix) expert
  4. to connect
  5. to communicate
  6. open
  7. to clear
  8. classifier for letters, telegrams, phone calls etc