viewing vs screening

viewing and screening both are nouns.

Word	Noun	Adjective	Verb	Adverb
viewing	Yes	No	No	No
screening	Yes	No	No	No

As nouns, viewing and screening are synonyms defined as:

Other synonyms of viewing include showing.

viewing (noun)	screening (noun)
a vigil held over a corpse the night before burial	the act of concealing the existence of something by obstructing the view of it
the display of a motion picture	testing objects or persons in order to identify those with particular characteristics
	fabric of metal or plastic mesh
	the display of a motion picture