The most common and most likely answer to this crossword clue is the 10 letter word PIXILATION
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Buddy explains!

The straight part
We know that "being slightly crazy" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case being slightly crazy = pixilation.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 PIXILATION mean?
PIXILATION noun- A stop-motion technique where live actors are used as a frame-by-frame subject in an animated film, by repeatedly posing while one or more frame is taken and changing pose slightly before the next frame or frames.
- A blocky effect caused by enlarging a bitmap so that individual pixels can be distinguished.
- The obscuring or censoring of part of an image by reducing the resolution, resulting in a blocky blur.