Adjectives, Conjunctions, Adverbs.
(1) Other parts of speech used as nouns:-
The great, the wealthy, fear thy blow.-Burns.
Every why hath a wherefore.-Shakespeare.
When I was young? Ah, woeful When!
Ah! for the change 'twixt Now and Then!
-Coleridge.
(2) Certain word groups used like single nouns:-
Too swift arrives as tardy as too slow.-Shakespeare.
Then comes the "Why, sir!" and the "What then, sir?" and the "No, sir!" and the "You don't see your way through the question, sir!"-Macaulay
(3) Any part of speech may be considered merely as a word, without reference to its function in the sentence; also titles of books are treated as simple nouns.
The it, at the beginning, is ambiguous, whether it mean the sun or the cold.-Dr BLAIR
In this definition, is the word "just," or "legal," finally to stand?-Ruskin.
There was also a book of Defoe's called an "Essay on Projects," and another of Dr. Mather's called "Essays to do Good."-B. FRANKLIN.
Caution.