Is able to get led astray by a light (6)
I believe the answer is:
candle
'a light' is the definition.
(candle is a kind of light)
'is able to get led astray' is the wordplay.
'is able to' becomes 'can' (I've seen this before).
'get' is a charade indicator (letters next to each other).
'astray' indicates an anagram.
'led' is an anagram of 'dle'.
'can'+'dle'='CANDLE'
'by' is the link.
(Other definitions for candle that I've seen before include "that's useful if power's cut" , "Lanced (anag)" , "Wax cylinder" , "Wax 21 ac source" , "Maeve Binchy novel 'Light a Penny ......'" .)