The most common and most likely answer to this crossword clue is the 8 plus 1 plus 5 letter word SPENDING A PENNY
I've seen this crossword clue in The Times
S
P
E
N
D
I
N
G
A
P
E
N
N
Y
Buddy explains!
The straight part
We know that "Visiting gents" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case visiting gents = spending a penny.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.