The most common and most likely answer to this crossword clue is the 8 letter word CHEMICAL
I've seen this crossword clue in Financial Times
C
H
E
M
I
C
A
L
More clues leading to the result CHEMICAL
- One may react with surprising malice after church
- Caught Michael shaking for addictive drug
- Substance affected Michael Caine’s head
- Caught Alchemi cycling in compound?
- Reaction to cooking chic meal
- Man replaces hole in funny compound?
- Guerrilla with remarkable claim relating to a type of warfare?
- Ludicrous to replace gas with another substance
Buddy explains!
The straight part
We know that "Reaction" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case reaction = chemical.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 CHEMICAL mean?
CHEMICAL noun- Any specific chemical element or chemical compound or alloy.
- An artificial chemical compound.
- An addictive drug.
- Of or relating to chemistry.
- Of or relating to a material or processes not commonly found in nature or in a particular product.
- Of or relating to alchemy.