The most common and most likely answer to this crossword clue is the 6 letter word PUKING
I've seen this crossword clue in The Guardian
P
U
K
I
N
G
Buddy explains!
The straight part
We know that "throwing up" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case throwing up = puking.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 PUKING mean?
PUKING verb- To vomit; to throw up; to eject from the stomach.
- To sell securities or investments at a loss, often under duress or pressure, in order to satisfy liquidity or margin requirements, or out of a desire to exit a deteriorating market.
- The act of one who pukes or vomits.