No this is ineffective: cut into small pieces (4)
I believe the answer is:
dice
This clue might be a double definition.
'no this is ineffective' is the first definition.
The definition suggests a singular noun which matches the answer.
'cut into small pieces' is the second definition.
The definition and answer can be both to do with contact as well as being verbs in their base form.
Maybe you can see a link between them that I can't see?
Can you help me to learn more?
(Other definitions for dice that I've seen before include "Gamble; cut into cubes" , "Take a risk" , "Small cube" , "Numbered cube(s)" , "Gaming cube(s)" .)