The most common and most likely answer to this crossword clue is the 8 letter word STAGNATE
S
T
A
G
N
A
T
E
More clues leading to the result STAGNATE
- Get stuck in street with any number jammed in an entrance
- Fly in food sent back? Do nothing
- Lie about insect being in food that's sent back
- Fail to develop stage, involving nationalist just briefly
- Stand in part of theatre, including nationally acclaimed trio, initially
- Decline food served up with squashed fly
- Insect dropped into food from the east – do nothing
- Food stuffed with strong flavour about to turn foul
- Stand still! Deer never attack the elderly, for starters
- Keep still, by the way, and relatively close
Buddy explains!

The straight part
We know that "Fail to develop" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fail to develop = stagnate.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 STAGNATE mean?
STAGNATE verb- To cease motion, activity, or progress: