The most common and most likely answer to this crossword clue is the 8 letter word EUPHORIA
I've seen this crossword clue in The Guardian
E
U
P
H
O
R
I
A
More clues leading to the result EUPHORIA
- Ecstasy bachelor extracted from plant
- Transport barrels out of plant
- Plant left by bishop causes elation
- United in hope, excited by revolutionary song giving joy
- Joy from pie author cooked, after temperature’s dropped
- Joining you for broadcast, I get a rapturous feeling
- Happy house passed around by rising river — that’s extreme happiness!
- “Eh up!”, pants Spice Girl appearing halfway through Glee
- Joy‘s plant, left by bishop
- Plant bachelor neglected creating joy
Buddy explains!
The straight part
We know that "extreme happine" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case extreme happine = euphoria.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 EUPHORIA mean?
EUPHORIA noun- An excited state of joy; a feeling of intense happiness.