The most common and most likely answer to this crossword clue is the 7 letter word FATALLY
I've seen this crossword clue in The Daily Telegraph
F
A
T
A
L
L
Y
More clues leading to the result FATALLY
- Terminally overweight friend
- They run football match catastrophically
- Stout supporter producing disastrous result
- Helper carrying pot in decisive manner
- Lay flat out with no hope of revival
- Footballers agree with a deadly final ending?
- . Number of deaths – it makes way to take fifty lethally
- Overweight friend with a terrible outcome
Buddy explains!

The straight part
We know that "with no hope of revival" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case with no hope of revival = fatally.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 FATALLY mean?
FATALLY adverb- In a fatal manner; lethally.
- Ultimately, with finality or irrevocability, moving towards the demise of something.
- Fatedly; according to the dictates of fate or doom.