The most common and most likely answer to this crossword clue is the 1 plus 8 plus 1 plus 5 letter word O TEMPORA, O MORES
I've seen this crossword clue in The Guardian
O
T
E
M
P
O
R
A
,
O
M
O
R
E
S
Buddy explains!
The straight part
We know that "lament about Roman corruption/lament about Roman corruption" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case lament about roman corruption/lament about roman corruption = o tempora, o mores.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.