An abstract noun denotes something intangible —a quality or state; a concrete noun denotes the person or thing that may possess that quality or be in that state. Thus man is concrete and humanity abstract, brain concrete and thought abstract. Abstract nouns are indispensable in their proper places. But one of the greatest faults of present-day writing is to use them to excess. There are two reasons why this is bad. First, it means that statements are made in a roundabout instead of a direct way, and the meaning is more difficult to grasp. The commonest form of roundabout is to make an abstract noun the subject of a sentence which would be clearer and more natural if its subject were a concrete noun or a personal pronoun — to say, for example, "was this the realisation of an anticipated liability?" instead of "did you expect you would have to do this?" Secondly, abstract nouns have less precise meanings than concrete ones, and therefore should be avoided as far as possible by those who wish to make their meaning plain. There is not room for wide variation in the interpretation by different people of such words as house and ship. But there is infinite room for differences of opinion about what is meant by such words as liberty and democracy.
Unfortunately the very vagueness of abstract words is one of the reasons for their popularity. To express one's thoughts accurately is hard work, and to be precise is sometimes dangerous. We are tempted to prefer the safer obscurity of the abstract. To resist this temptation, and to resolve to make your meaning plain to your reader even at the cost of some trouble to yourself, is more important than any other single thing if you would convert a flabby style into a crisp one. As Mr. G. M. Young has said, an excessive reliance on the noun at the expense of the verb will, in the end, detach the mind of the writer from the realities of here and now, from when and how and in what mood the thing was done, and insensibly induce a habit of abstraction, generalisation and vagueness.
Here are five examples of the roundabout abstract phrase and two of sentences which have been made almost unintelligible by an excessive reliance on abstract words.