The most common and most likely answer to this crossword clue is the 8 letter word FUNEREAL
I've seen this crossword clue in Financial Times
F
U
N
E
R
E
A
L
More clues leading to the result FUNEREAL
- Following diversion, ultimately become very gloomy
- Dismal end of marriage – authentic amusement comes first
- Amusing queen brewed ale that’s dark
- Slow and enjoyable breakfast dish, not cold
- Entertaining — before a Liberal becomes dismal
- Enjoyment before almost everyone becomes gloomy
- Woeful enjoyment before a library’s opening
- Gloomy fellow invented cloaking device at last
- Dismal entertainment with ‘Last Of The Summer Wine’ absolute bottom of barrel
- Very slow, but enjoyment finally became genuine
Buddy explains!

The straight part
We know that "Dismal" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case dismal = funereal.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 FUNEREAL mean?
FUNEREAL adjective- Of or relating to a funeral.
- Similar to a funeral in mood; dignified or solemn.