Jumblies' craft is returned the night before (5)
I believe the answer is:
sieve
'jumblies' craft' is the definition.
I can't judge whether this definition defines the answer.
'is returned the night before' is the wordplay.
'returned' says the letters should be written in reverse.
'the night before' becomes 'eve' (eve can mean the night before something).
'is' in reverse letter order is 'si'.
'si'+'eve'='SIEVE'
Can you help me to learn more?
(Other definitions for sieve that I've seen before include "particle separator" , "Eratosthenes' invention" , "Screen, sift, strain" , "Utensil for straining or sifting food" , "Craft for Jumblies" .)