The most common and most likely answer to this crossword clue is the 15 letter word DISCOUNTENANCED
I've seen this crossword clue in The Daily Telegraph
D
I
S
C
O
U
N
T
E
N
A
N
C
E
D
Buddy explains!
The straight part
We know that "not approved of" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case not approved of = discountenanced.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 DISCOUNTENANCED mean?
DISCOUNTENANCED verb- To have an unfavorable opinion of; to deprecate or disapprove of.
- To abash, embarrass or disconcert.
- To refuse countenance or support to; to discourage.
- Deprecated
- Disliked