Child's plaything (6)
(Other definitions for rattle that I've seen before include "Irritating sound" , "Child's toy; unsettle" , "Baby's toy; sound of something loose" , "Trivial talk" , "Baby's toy - conductor" .)
'child's plaything' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for doll that I've seen before include "Child's plaything" , "Small replica of a person" , "Puppet" , "Toy baby" , "Toy in human form" .)