loss vs wastage

loss and wastage both are nouns.

Word	Noun	Adjective	Verb	Adverb
loss	Yes	No	No	No
wastage	Yes	No	No	No

As nouns, wastage is a hyponym of loss; that is, wastage is a word with a more specific, narrower meaning than loss:

Other hyponyms of loss include forfeit, forfeiture, financial loss, sacrifice.

loss (noun)	wastage (noun)
the act of losing someone or something	anything lost by wear or waste
the disadvantage that results from losing something	the process of wasting
military personnel lost by death or capture
the experience of losing a loved one
euphemistic expressions for death
the amount by which the cost of a business exceeds its revenue
something that is lost
gradual decline in amount or activity