The most common and most likely answer to this crossword clue is the 4 letter word MIDI
I've seen this crossword clue in Financial Times
M
I
D
I
More clues leading to the result MIDI
- Garment for the female aforesaid improperly reveals back
- Skirt Mudd had, Mudd is returning
- Some vivid imagination to lift skirt!
- One lacking intelligence brought up in part of France
- Coat for the South of France
- Dress for the South of France
- One not very bright turned up in a sort of skirt
- Dress for the South of France?
- I become faint after lifting skirt
- Skirt around saying nothing extra
Buddy explains!

The straight part
We know that "skirt" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case skirt = midi.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 MIDI mean?
MIDI noun- A native or inhabitant of Berlin.
- A doughnut with a sweet filling.
- A newspaper format with pages normally measuring about 315 by 470 millimetres (12.4 in × 18.5 inches), slightly taller and wider than a tabloid but narrower and shorter than a broadsheet.
- A coat or skirt having such a hemline.
- Having a hemline at mid-calf length.