Light vessel gets led astray (6)
I believe the answer is:
candle
'light' is the definition.
(candle is a kind of light)
'vessel gets led astray' is the wordplay.
'vessel' becomes 'can' (I've seen this before).
'gets' says to put letters next to each other.
'astray' indicates anagramming the letters.
'led' anagrammed gives 'dle'.
'can'+'dle'='CANDLE'
(Other definitions for candle that I've seen before include "Maeve Binchy novel 'Light a Penny ......'" , "Means of illumination" , "It's better to light one than curse the darkness, it's said" , "may be too expensive for game" , "Artificial light" .)