The most common and most likely answer to this crossword clue is the 9 letter word INNKEEPER
I've seen this crossword clue in The Sunday Telegraph
I
N
N
K
E
E
P
E
R
More clues leading to the result INNKEEPER
- Fashionable ring worn by northern publican
- In secret, observe landlord
- Landlord to observe in secret
- Landlord's sly look up inside skirts
- Bar manager from sounding out popular goalie
- Hot new goalie, one reportedly denying Jesus room on his first appearance
- Essential job description for Winnie!
- Look up, interrupting central host
- Publican’s secret stock inside
- Carry on blocking exclusive or private landlord
Buddy explains!
The straight part
We know that "one fully booked before Christmas" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one fully booked before christmas = innkeeper.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does INNKEEPER mean?
INNKEEPER noun- The person responsible for the running of an inn, usually the proprietor.