The most common and most likely answer to this crossword clue is the 9 letter word OVERSPILL
I've seen this crossword clue in The Guardian
O
V
E
R
S
P
I
L
L
More clues leading to the result OVERSPILL
- Too sick to take in afterthought about displaced population?
- Excess fluid covers pillow somewhat
- Maidens possibly quiet and unwell – a waste of lager?
- Excessive gushing from paramours wanting large contraceptive
- Quietly sick after bowling an excessive amount
- Relocated residents, concerned with drugs, end westernmost
- Spell that’s prescribed for displaced people?
- In the past small price increases initially left fifty people moving from crowded city
- People outside city have extra parts exchanged
- Have too much juice without starting Viagra?
Buddy explains!

The straight part
We know that "Excessive gushing" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case excessive gushing = overspill.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 OVERSPILL mean?
OVERSPILL noun- That which spills over.
- To spill over, to overflow, to spill out of.