The most common and most likely answer to this crossword clue is the 9 letter word GLUTINOUS
I've seen this crossword clue in The Times
G
L
U
T
I
N
O
U
S
More clues leading to the result GLUTINOUS
Buddy explains!
The straight part
We know that "sticky" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case sticky = glutinous.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 GLUTINOUS mean?
GLUTINOUS adjective- Glue-like, sticky, viscid.
- Of the nature of gluten.
- Containing gluten.