The most common and most likely answer to this crossword clue is the 14 letter word MISAPPROPRIATE
I've seen this crossword clue in The Guardian
M
I
S
A
P
P
R
O
P
R
I
A
T
E
More clues leading to the result MISAPPROPRIATE
- Motorway speed limits fool rugby player? One’s held in nick
- Most of film fitting in pocket
- Is involved in plan for getting pirate out of nick
- Nick, married, is suitable
- Following endless failure, apt to embezzle
- Nick is apt to support Mike
- Nick is essential to plan to support one in charge
- Medicine, at first, is right to take
- Rob‘s pronouncement of a woman who’s suitable?
Buddy explains!

The straight part
We know that "Rob" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case rob = misappropriate.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 MISAPPROPRIATE mean?
MISAPPROPRIATE verb- To take something for wrong or illegal purposes.
- To embezzle.