The most common and most likely answer to this crossword clue is the 10 letter word UNWEARABLE
I've seen this crossword clue in Independent
U
N
W
E
A
R
A
B
L
E
More clues leading to the result UNWEARABLE
Buddy explains!
The straight part
We know that "it’s not good to assume" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case it’s not good to assume = unwearable.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 UNWEARABLE mean?
UNWEARABLE noun- Something, such as clothing, that cannot be worn
- Not able to be worn