The most common and most likely answer to this crossword clue is the 8 letter word SENSIBLE
I've seen this crossword clue in The Daily Telegraph
S
E
N
S
I
B
L
E
More clues leading to the result SENSIBLE
- Able to feel bliss, even not very upset
- Reasonable review of Ibsen’s leading characters in Little Eyolf
- Left bins out in sight? That’s wise
- Displaying either component of a novel by a lady
- One musically wowing British Isles, touring Lowestoft/Unst locations
- Bursting in, be less coolheaded
- Practical is ‘in’ — be less fancy
- Possibly no good being less wise
- Eccentric mostly being less realistic
- Drunk is seen outside British Library, initially sober
Buddy explains!

The straight part
We know that "sober" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case sober = sensible.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 SENSIBLE mean?
SENSIBLE noun- Sensation; sensibility.
- That which impresses itself on the senses; anything perceptible.
- That which has sensibility; a sensitive being.
- Perceptible by the senses.
- Easily perceived; appreciable.
- Able to feel or perceive.
- Liable to external impression; easily affected; sensitive.
- Of or pertaining to the senses; sensory.
- Cognizant; having the perception of something; aware of something.
- Acting with or showing good sense; able to make good judgements based on reason.
- Characterized more by usefulness or practicality than by fashionableness, especially of clothing.