The most common and most likely answer to this crossword clue is the 6 letter word PLACED
I've seen this crossword clue in The Guardian
P
L
A
C
E
D
Buddy explains!
The straight part
We know that "Put/third at worst" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case put/third at worst = placed.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 PLACED mean?
PLACED verb- To put (an object or person) in a specific location.
- To earn a given spot in a competition.
- To remember where and when (an object or person) has been previously encountered.
- (in the passive) To achieve (a certain position, often followed by an ordinal) as in a horse race.
- To sing (a note) with the correct pitch.
- To arrange for or to make (a bet).
- To recruit or match an appropriate person for a job.
- To place-kick (a goal).