The most common and most likely answer to this crossword clue is the 6 letter word EMOJIS
E
M
O
J
I
S
Buddy explains!
The straight part
We know that "Graphic reactions" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case graphic reactions = emojis.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 EMOJIS mean?
EMOJIS noun- A digital graphic icon with a unique code point used to represent a concept or object, originally used in Japanese text messaging but since adopted internationally in other contexts such as social media.