Floppy disk for children (4)
I believe the answer is:
kids
'children' is the definition.
('kid' can be a synonym of 'child')
'floppy disk' is the wordplay.
'floppy' is an anagram indicator.
'disk' is an anagram of 'KIDS'.
'for' is the link.
(Other definitions for kids that I've seen before include "Young goats" , "Teases" , "Youngsters" , "Children" , "They make immature butts" .)