The most common and most likely answer to this crossword clue is the 7 letter word NAIADES
N
A
I
A
D
E
S
More clues leading to the result NAIADES
Buddy explains!

The straight part
We know that "spirits" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case spirits = naiades.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 NAIADES mean?
NAIADES noun- A female deity (nymph) associated with water, especially a spring, stream, or other fresh water.
- The aquatic larva (nymph) of a dragonfly or damselfly.
- Any of various aquatic plants of the genus Najas.