The most common and most likely answer to this crossword clue is the 10 letter word DISCONCERT
I've seen this crossword clue in The Guardian
D
I
S
C
O
N
C
E
R
T
More clues leading to the result DISCONCERT
- Throw candleholder into mire
- Insult politician with something sure to upset
- Throw dance party close to Oban? Sure thing!
- Record on, sure thing to upset
- Throw party before noon? Sure thing
- Upset to find candlestick covered with muck
- Recording being played: something sure to provide surprise
- Band’s ending — is gig put off?
- Company shared in club entertainment creates shock
- Prior to musical event duke is upset
Buddy explains!

The straight part
We know that "Throw" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case throw = disconcert.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 DISCONCERT mean?
DISCONCERT noun- A state of disunion.
- To upset the composure of.
- To bring into confusion.
- To frustrate, discomfit.