Arrange letters for a while (5)
I believe the answer is:
spell
This clue is a double definition.
'arrange letters' is the first definition.
(I've seen this in another clue)
'while' is the second definition.
(I've seen this in another clue)
'for a' is the link.
(Other definitions for spell that I've seen before include "something to cast" , "Charm; short period" , "Name in order the letters of the alphabet involved" , "Stretch" , "Give out letters" .)