The most common and most likely answer to this crossword clue is the 8 letter word OUTDOORS
O
U
T
D
O
O
R
S
Buddy explains!

The straight part
We know that "alfresco" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case alfresco = outdoors.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 OUTDOORS mean?
OUTDOORS noun- (often preceded by "the") The environment outside of enclosed structures.
- (often preceded by "the") The natural environment in the open air, countryside away from cities and buildings.
- Not inside a house or under covered structure; unprotected; in the open air.