Stretch over, has a rest (4)
I believe the answer is:
naps
'has a rest' is the definition.
I can't judge whether this definition defines the answer.
'stretch over' is the wordplay.
'stretch' becomes 'span' (I've seen this before).
'over' says the letters should be written backwards.
'span' reversed gives 'NAPS'.
Can you help me to learn more?
(Other definitions for naps that I've seen before include "Span including short sleeps" , "Takes forty winks" , "Tips; sleeps" , "Snoozes" .)