Charm for short period (5)
I believe the answer is:
spell
I believe this clue is a double definition.
'charm' is the first definition.
(both can mean a bit of magic)
'short period' is the second definition.
(I've seen this in another clue)
'for' acts as a link.
(Other definitions for spell that I've seen before include "Trance" , "Deliveries" , "Stretch" , "Incantation; splinter of wood" , "Fascination" .)