The most common and most likely answer to this crossword clue is the 8 letter word PUGILIST
I've seen this crossword clue in The Guardian
P
U
G
I
L
I
S
T
More clues leading to the result PUGILIST
- Boxer dog and this setter roll
- Boxer dog I advertise for sale
- Breed of dog, one lean aggressive type
- One wearing gloves turns over private bank
- Boxer backed up against fighter that’s lean
- One fighting guilt is sadly under pressure
- Boxer dog given instruction, initially, to “heel”
- Fighter turning up on US muster roll?
- I incline to follow dog — boxer?
- Dog I catalogue as boxer
Buddy explains!

The straight part
We know that "Boxer" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case boxer = pugilist.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 PUGILIST mean?
PUGILIST noun- One who fights with his fists; especially a professional prize fighter; a boxer.