The most common and most likely answer to this crossword clue is the 3 plus 2 plus 3 letter word MAN TO MAN
I've seen this crossword clue in The Guardian
M
A
N
T
O
M
A
N
More clues leading to the result MAN TO MAN
Buddy explains!
The straight part
We know that "How fellows talk openly/of a marking system/excluding females" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case how fellows talk openly/of a marking system/excluding females = man to man.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 MAN TO MAN mean?
MAN TO MAN adjective- Direct, forthright and honest
- One-on-one
- Directly, forthrightly and honestly