### Clue: 20's colleague initially denied Jewish tribe (6)
### Answer: DASHER 
 ### Explanation: Definition: 20's colleague
 **1st letter of**(initially) "denied" + ASHER(a Jewish tribe named after its founder, son of Jacob and Zilpah in the Book of Genesis.
Defn: Dancer(answer to 20)'s colleague in Santa Claus's sleigh-pulling team of reindeer.
Pub quiz question: Name Santa's reindeer.