The most common and most likely answer to this crossword clue is the 5 plus 1 plus 5 plus 3 letter word TURNS A BLIND EYE
I've seen this crossword clue in The Daily Telegraph
T
U
R
N
S
A
B
L
I
N
D
E
Y
E
Buddy explains!
The straight part
We know that "Takes no notice of" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case takes no notice of = turns a blind eye.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.