... from the jumble to allow (3)
I believe the answer is:
let
'allow' is the definition.
(I know that allow can be written as let)
'from the jumble to' is the wordplay.
'from' says the answer is hidden in the clue.
'LET' can be found hidden inside 'jumble to'.
(Other definitions for let that I've seen before include "Allow - hire" , "Allow; rental period" , "Allow or rent" , "Permit; lease" , "inefficient service" .)