At first light it DOES sound a bit confusing. First, the definition of the term 'NON-LUMINOUS'; 'Not capable of PRODUCING light but can be capable of REFLECTING light from another source'. For...
light which do not give out their own light
"Luminous" means emitting light (conveniently measured in units known as Lumens). Synonym would most often be "glowing".
Luminous light is a light source but another name for it.
Yes.