The most common and most likely answer to this crossword clue is the 9 letter word OVERSWEET
I've seen this crossword clue in The Guardian
O
V
E
R
S
W
E
E
T
Buddy explains!
The straight part
We know that "Not to one’s taste and bad for one" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case not to one’s taste and bad for one = oversweet.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 OVERSWEET mean?
OVERSWEET adjective- Too sweet; excessively sweet.