The most common and most likely answer to this crossword clue is the 8 letter word SPENDING
I've seen this crossword clue in Financial Times
S
P
E
N
D
I
N
G
More clues leading to the result SPENDING
Buddy explains!

The straight part
We know that "Lashing out" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case lashing out = spending.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 SPENDING mean?
SPENDING noun- Present participle of spend, expenditure.
- An amount that has been, or is planned to be spent.
- To pay out (money).
- To bestow; to employ; often with on or upon.
- To squander.
- To exhaust, to wear out.
- To consume, to use up (time).
- To have an orgasm; to ejaculate sexually.
- To waste or wear away; to be consumed.
- To be diffused; to spread.
- To break ground; to continue working.