The most common and most likely answer to this crossword clue is the 9 letter word MANSPLAIN
I've seen this crossword clue in Independent
M
A
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More clues leading to the result MANSPLAIN
Buddy explains!
The straight part
We know that "tell woman what’s what" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case tell woman what’s what = mansplain.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 MANSPLAIN mean?
MANSPLAIN verb- To explain (something) condescendingly (to a female listener), especially to explain something the listener already knows, presuming that she has an inferior understanding of it merely because she is female.