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

1. (dialectal) continuously; constantly
2. (literary) a door
3. (literary) a single source; a single origin
4. (literary) a way; a means
5. a cannon
6. a door
7. a family; a clan
8. a kind; the same kind
9. a single source; a single origin
10. a skill
11. a style; a faction; a denomination
12. a subject of study
13. a way; a means
14. an event or occurrence
15. continuously; constantly
16. the same school or teacher

classifier: 門

1. to need; to want; to demand; to require
2. needs

1. very; quite
2. (also, often used before an adjective without intensifying its meaning, i.e. as a meaningless syntactic element)