n.[C]

1. （封建時代的）諸侯；封臣
2. 從屬者；下屬
3. 家臣；奴僕；奴隸

a.[B]

1. 臣的；附庸的
   Wales was a vassal kingdom at that time.

   那時威爾士是個附庸國。

2. 奴僕的；奴隸的

n.

1. historical a holder of land by feudal tenure on conditions of homage and allegiance.
2. a person or country in a subordinate position to another.