The most common and most likely answer to this crossword clue is the 9 letter word PREVALENT
I've seen this crossword clue in The Daily Telegraph
P
R
E
V
A
L
E
N
T
More clues leading to the result PREVALENT
- Common old man fed by priest before fast
- Common little man seen in bar
- Stop enclosing area on large common
- Dominant reverend father’s around after Ash Wednsday
- Stop a student entering common
- Common fellow found in bar
- Having a litre in bar is common
- Pressure on cleric before a Christian observance is common
- Common pal never dances tango
- Avoid importing a large epidemic
Buddy explains!

The straight part
We know that "Usual" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case usual = prevalent.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 PREVALENT mean?
PREVALENT adjective- Widespread or preferred.
- Superior in frequency or dominant.