The most common and most likely answer to this crossword clue is the 7 letter word SNEEZES
S
N
E
E
Z
E
S
Buddy explains!
The straight part
We know that "Has a cold reaction" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case has a cold reaction = sneezes.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 SNEEZES mean?
SNEEZES noun- An act of sneezing.
- To expel air as a reflex induced by an irritation in the nose.
- To expel air as if the nose were irritated.