The most common and most likely answer to this crossword clue is the 12 letter word WASHER-DRYER
I've seen this crossword clue in The Times
W
A
S
H
E
R
-
D
R
Y
E
R
More clues leading to the result WASHER-DRYER
Buddy explains!
The straight part
We know that "What" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case what = washer-dryer.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 WASHER-DRYER mean?
WASHER-DRYER noun- An machine that combines a washing machine and clothes dryer.