Supplier of narrow light dinghy (5)
I believe the answer is:
laser
This clue is a double definition.
'supplier of narrow light' is the first definition.
'dinghy' is the second definition.
(Laser is a brand of dinghies)
(Other definitions for laser that I've seen before include "Powerful light source" , "Device producing thin beam of light" , "modern light industry" , "Intense and concentrated beam of light" , "Device producing an intense light beam - kind of sailing dinghy" .)