The most common and most likely answer to this crossword clue is the 2 letter word KO
I've seen this crossword clue in The Times
K
O
More clues leading to the result KO
Buddy explains!
The straight part
We know that "He had a list" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case he had a list = ko.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 KO mean?
KO noun- (game of go) A local shape to which the ko rule applies; a ko shape.
- (game of go) ko fight
- (game of go) a stone in a ko in atari, a ko stone