Light touch making you sound radical (5)
I believe the answer is:
torch
'light' is the definition.
(type of light)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for torch that I've seen before include "Set fire to (something)" , "Source of light" , "Link" , "Set alight deliberately" , "Small portable battery-powered electric lamp" .)