The most common and most likely answer to this crossword clue is the 8 letter word ALFRESCO
I've seen this crossword clue in Financial Times
A
L
F
R
E
S
C
O
More clues leading to the result ALFRESCO
- A Liberal painting in the open air
- Bananas for sale getting cold in open air
- I will avoid various coal-fires out of doors
- Slave back in shifting coal out of doors
- Old King’s company ditching Director outside
- Close? Far? Out – that is, not in the house
- Flares set off by officer in the open
- Backed slave distributing coal outside – outside!
- Duke excluded from king’s company outside
- Learner pursues first in Art painting outdoors
Buddy explains!

The straight part
We know that "outside" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case outside = alfresco.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 ALFRESCO mean?
ALFRESCO adjective- Outdoors, open to the atmosphere.
- Outdoors; in fresh air.
- Onto fresh plaster that is still moist.