Slide for small child (4)
I believe the answer is:
skid
'slide' is the definition.
(I know that slide can be written as skid)
'small child' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'child' becomes 'kid' (synonyms).
's'+'kid'='SKID'
'for' acts as a link.
(Other definitions for skid that I've seen before include "Slide along without control" , "Slip on wet ground" , "Swerve out of control" , "Slide (on slippery ground)" , "What car may do on ice - be careful" .)