The most common and most likely answer to this crossword clue is the 11 letter word INCOMPETENT
I've seen this crossword clue in The Daily Telegraph
I
N
C
O
M
P
E
T
E
N
T
More clues leading to the result INCOMPETENT
- Proceeds to cover favourite books? That's useless
- Foolishly in contempt over the introduction of evidence when not legally qualified
- Useless cop in Met sloppily inclined to ignore lead
- Unable to get pay, keeping quiet, needing temporary shelter
- Inability to take part in contest in pub against the church
Buddy explains!

The straight part
We know that "Unable to get" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case unable to get = incompetent.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 INCOMPETENT mean?
INCOMPETENT noun- A person who is incompetent.
- Unskilled; lacking the degree of ability that would normally be expected.
- Unable to make rational decisions, insane or otherwise cognitively impaired.
- Of the cervix: opening too early in pregnancy, provoking the baby to be born.
- Not resistant to deformation or flow.