Light suit's covering gown (6)
I believe the answer is:
strobe
'light' is the definition.
(strobe light is a type of light)
'suit's covering gown' is the wordplay.
'covering' suggests removing the centre (the letters which cover the word are used).
'gown' becomes 'robe' (synonyms).
'suit' with its middle removed is 'st'.
'st'+'robe'='STROBE'
(Other definitions for strobe that I've seen before include "Flasher" , "Flashy type" , "Light that seems to spin" , "Sorbet (anag) -flashing light" , "Flashing, very bright beam" .)