The most common and most likely answer to this crossword clue is the 10 letter word BLOODSTOCK
I've seen this crossword clue in The Daily Telegraph
B
L
O
O
D
S
T
O
C
K
More clues leading to the result BLOODSTOCK
Buddy explains!
The straight part
We know that "us" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case us = bloodstock.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 BLOODSTOCK mean?
BLOODSTOCK noun- Thoroughbred animals in general, but especially horses.
- The breeding line of a thoroughbred horse or other animal.