The most common and most likely answer to this crossword clue is the 11 letter word DISTRACTING
I've seen this crossword clue in The Daily Telegraph
D
I
S
T
R
A
C
T
I
N
G
Buddy explains!

The straight part
We know that "off-putting" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case off-putting = distracting.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 DISTRACTING mean?
DISTRACTING verb- To divert the attention of.
- To make crazy or insane; to drive to distraction.