The most common and most likely answer to this crossword clue is the 8 letter word RETARDED
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Buddy explains!

The straight part
We know that "hindered" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case hindered = retarded.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 RETARDED mean?
RETARDED verb- To keep delaying; to continue to hinder; to prevent from progress
- To put off; to postpone.
- To be slow or dilatory to perform (something).
- To decelerate; to slow down.
- To stay back.
- Delayed; delayed in development, hindered; impeded.
- Having mental retardation; mentally deficient or underdeveloped.
- Specifically, having an IQ below 70.
- Extremely stupid.
- Designating a parameter of an electromagnetic field which is adjusted to account for the finite speed of radiation.