Mention freer arrangement (5)
I believe the answer is:
refer
'mention' is the definition.
(I know that mention can be written as refer)
'freer arrangement' is the wordplay.
'arrangement' indicates anagramming the letters.
'freer' anagrammed gives 'REFER'.
(Other definitions for refer that I've seen before include "Fail (an exam candidate)" , "Advert, mention" , "Be relevant (to)" , "Pertain; assign" , "If special treatment needed, GP might do this" .)