The most common and most likely answer to this crossword clue is the 8 letter word UNBEATEN
I've seen this crossword clue in Financial Times
U
N
B
E
A
T
E
N
More clues leading to the result UNBEATEN
- A French cookery writer reportedly never surpassed
- Been playing with aunt yet to lose
- Left bishop inside, yet to lose
- Left, accepting bishop is yet to lose
- Like leftovers with a slice of bacon tucked in? Always a winner
- Fresh bun swallowed, though never taken down?
- Victorious, like an exemplary public schoolboy of old?
- In run, be a tenth on a winning streak?
- Supreme Being originally consumed by excess
- Not licked, like eggs before baking?
Buddy explains!

The straight part
We know that "yet to lose" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case yet to lose = unbeaten.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 UNBEATEN mean?
UNBEATEN adjective- Not having been thrashed or beaten
- Not defeated
- Untrodden
- Not beaten or whisked
- Not out