We don't have synonyms for light-years yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are light, plight and sight.
(n) :
a small, reusable, handheld device for creating fire; a flat-bottomed boat for carrying heavy loads across short distances (especially for canals or for loading or unloading larger boats)
"cigarette in mouth, he clutched his pockets in search of a lighter."
(n) :
a small, reusable, handheld device for creating fire; a flat-bottomed boat for carrying heavy loads across short distances (especially for canals or for loading or unloading larger boats)
"cigarette in mouth, he clutched his pockets in search of a lighter."