The most common and most likely answer to this crossword clue is the 8 letter word UNVERSED
I've seen this crossword clue in The Times
U
N
V
E
R
S
E
D
Buddy explains!

The straight part
We know that "Not skilled" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case not skilled = unversed.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 UNVERSED mean?
UNVERSED adjective- Inexperienced, untrained.
- Not expressed in verse, unversified.