The most common and most likely answer to this crossword clue is the 4 letter word COMA
C
O
M
A
More clues leading to the result COMA
- Take care of the old woman showing sign of severe illness?
- Choice of mild anaesthetic initially prolonged unconsciousness
- The old woman backing firm in an unhealthy state
- Unconscious state
- Sensible patients wouldn’t be in it
- Head of space body is cold, woman discovered
- Mark loses heart in a state of stupor
- Prolonged unconsciousness leads to cessation of mental activity
- About to take mantra to get into deep sleep
- In the smallest interval, money is lost resulting in a senseless state
Buddy explains!

The straight part
We know that "deep sleep" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case deep sleep = coma.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 COMA mean?
COMA noun- A state of unconsciousness from which one may not wake up, usually induced by some form of trauma.
- A cloud of dust surrounding the nucleus of a comet.
- A defect characterized by diffuse, pear-shaped images that in an ideal image would appear as points.
- A tuft or bunch, such as the assemblage of branches forming the head of a tree, a cluster of bracts when empty and terminating the inflorescence of a plant, or a tuft of long hairs on certain seeds.