Spice children initially think the world of (5)
I believe the answer is:
clove
'spice' is the definition.
(clove is a kind of spice)
'children initially think the world of' is the wordplay.
'initially' indicates taking the first letters.
'think the world of' becomes 'love'.
The initial letter of 'children' is 'c'.
'c'+'love'='CLOVE'
(Other definitions for clove that I've seen before include "Spice, used whole or ground" , "Split; spice" , "Payment for hostage" , "Cut" , "Garlic segment" .)