The most common and most likely answer to this crossword clue is the 8 letter word HAS-BEEN
H
A
S
-
B
E
E
N
More clues leading to the result HAS-BEEN
- One past it, but still in possession of pulse, audibly
- Yesterday’s man is not entirely penniless, do we hear?
- A little laughter observed about bishop in yesterday’s news
- Banshee flying around one whose time is gone
- One who used to be known for keeping insect close to extinction
- Husband when defeated heartlessly is called a loser
Buddy explains!

The straight part
We know that "loser" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case loser = has-been.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 HAS-BEEN mean?
HAS-BEEN noun- A person, especially one formerly popular or influential, who continues in their field after their popularity or effectiveness has peaked and is now in decline.