The most common and most likely answer to this crossword clue is the 6 letter word SWINES
I've seen this crossword clue in The Guardian
S
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Buddy explains!

The straight part
We know that "Despicable types" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case despicable types = swines.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 SWINES mean?
SWINES noun- (plural swine) A pig (the animal).
- A contemptible person (plural swines).
- A police officer; a "pig".
- Something difficult or awkward; a pain.