The most common and most likely answer to this crossword clue is the 8 letter word UNVIABLE
U
N
V
I
A
B
L
E
More clues leading to the result UNVIABLE
Buddy explains!
The straight part
We know that "not likely to work" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case not likely to work = unviable.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 UNVIABLE mean?
UNVIABLE adjective- Unable to sustain its own life