Be quiet! Snoozes are said to be good for the spirit (8)
I believe the answer is:
schnapps
'the spirit' is the definition.
(I have seen 'Strong spirit ' mean 'schnapps' so perhaps 'spirit' could also mean 'schnapps')
'be quiet snoozes are said to be' is the wordplay.
I cannot really understand how this works, but
'quiet' could be 'pp' (musical abbreviation for pianissimo) and 'pp' is found within the answer.
'are' could be 'a' (short for 'are', historical unit of measurement) and 'a' is found within the answer.
This explanation may well be incorrect...
'good for' acts as a link.
Can you help me to learn more?
(Other definitions for schnapps that I've seen before include "Booze" , "Various strong spirits drunk in N Europe, consonant heavy" , "Strong drinks, Dutch gin made from potatoes say" , "Strong gin-like drink" , "Holland gin" .)