Random Riddle: Both Nouns and Adjectives

Some words can be used as both nouns and adjectives. In this teaser, you will be given a definition. That definition can be replaced by a single word that is used twice, once as an adjective, the other as a noun.

For example: “a 12-inch podiatrist specialty” is a “foot foot”.

Given the following four definitions, what are the corresponding doublets?

1) an underweight source of illumination
2) an ordinary prairie
3) a quick period of not eating
4) a cruel average
 

Random Riddle: Both Nouns and Adjectives