The most common and most likely answer to this crossword clue is the 4 letter word OPPO
I've seen this crossword clue in The Times
O
P
P
O
More clues leading to the result OPPO
- Loves welcoming very quiet colleague
- Counterpart works back to back
- Rival’s back-to-back works
- Colleague’s operation into which one goes
- Work, going forward and back, for counterpart
- Counterpart rings around very quietly
- Counterpart works, going east and west
- Surgery – evidently reversible – seen in China
- Equivalent of work pressure, love
- Colleague in work on left, not right
Buddy explains!
The straight part
We know that "colleague" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case colleague = oppo.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 OPPO mean?
OPPO noun- A friend, associate or colleague.
- Research into one's opponent's family, friends and past, which aims to uncover activities or interests which embarrass or discredit them (short for oppo research).