The most common and most likely answer to this crossword clue is the 6 letter word UNSEAT
I've seen this crossword clue in The Daily Telegraph
U
N
S
E
A
T
More clues leading to the result UNSEAT
- Throw Austen out
- Throw drink during pursuit of Cockney?
- Chuck out Austen novel
- Not firm catching a throw
- Throw aunties out? Not I!
- Throw Austen’s letters out
- Throw cakes without topping down
- Sisters tidy, both having misplaced one new throw
- Depose from position in Security Council
- Oust terrible aunts, embracing Bertie finally
Buddy explains!

The straight part
We know that "Oust" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case oust = unseat.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 UNSEAT mean?
UNSEAT verb- To throw from one's seat; to deprive of a seat.
- To deprive of the right to sit in a legislative body, as for fraud in election, or simply by defeating them in an election.