The most common and most likely answer to this crossword clue is the 6 letter word AMIDST
I've seen this crossword clue in The Guardian
A
M
I
D
S
T
More clues leading to the result AMIDST
- Surrounded by a fog, holding on to daughter
- In middle of morning, I’d emptied sachet
- In the middle of change it's mad
- Surrounded by 500 in a film
- Surrounded by a thin fog crossing end of field
- In a film, deception initially involved
- In the middle of Germany, stuck in some fog
- In the thick of a smog across delta
- In the thick of it, dam’s broken
- Maid lost on street at the Centre
Buddy explains!

The straight part
We know that "In the thick of it" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case in the thick of it = amidst.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 AMIDST mean?
AMIDST preposition- In the midst or middle of; surrounded or encompassed by; among.