The most common and most likely answer to this crossword clue is the 3 plus 5 letter word ALE HOUSE
I've seen this crossword clue in Financial Times
A
L
E
H
O
U
S
E
Buddy explains!

The straight part
We know that "pub" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case pub = ale house.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.
Crossword Answer definitions
ALE HOUSE noun- A business, such as an inn or tavern, where ale is sold.