Gathers disks without hesitation (7)
I believe the answer is:
puckers
'gathers' is the definition.
(I know this)
'disks without hesitation' is the wordplay.
'disks' becomes 'pucks' (puck is a kind of disk).
'without' means one lot of letters goes inside another ('without' can be similar in meaning to 'outside').
'hesitation' becomes 'er' (sound used when hesitating).
'pucks' enclosing 'er' is 'PUCKERS'.
(Other definitions for puckers that I've seen before include "Becomes wrinkled" , "Screws up" .)