Turning adjectives into nouns

The most productive suffix for adjectives of Latin origin is -ity: dense → density, rare → rarity, flexible → flexibility. Adjectives in -able/-ible give -ability/-ibility, as in compatible → compatibility and available → availability; those in -ous often give -osity or -ity, as in generous → generosity and anonymous → anonymity. The suffix -ness attaches to simple and compound adjectives, especially those in -ful, -less, -ing and -ed: kind → kindness, helpful → helpfulness. Adjectives in -ive use both patterns, with the choice fixed for the word: effective → effectiveness, but active → activity and sensitive → sensitivity. Final -y changes to -i-: happy → happiness.

Adjectives in -ant/-ent change to -ance/-ence or -ancy/-ency: relevant → relevance, absent → absence, frequent → frequency, urgent → urgency. The choice between -ce and -cy is fixed for the individual word and sometimes reflects a difference in meaning: dependence is a state of dependence, while dependency can be a dependent territory or situation. Learn the suffix with the word rather than choosing by a formula; check uncertain forms in a dictionary.

Not every noun is formed by adding -ity or -ness. Learn complete pairs: true → truth, warm → warmth, broad → breadth, high → height, wise → wisdom, brave → bravery, safe → safety, difficult → difficulty. Sometimes the spelling of the stem changes; sometimes a different word is chosen for the intended meaning, as in fast → speed. Other derivatives may exist but have a different nuance or be much rarer.

A separate trap is a shift in meaning. Busyness names the state of being busy, while business means an activity, enterprise or commercial matter. Ill gives illness, referring to sickness rather than a bad or malicious quality. If a noun is familiar but its meaning is wrong, check whether it actually corresponds to the adjective you intend.

When the adjective is negative, the prefix carries over into the noun: impossible → impossibility, irrelevant → irrelevance, dishonest → dishonesty, unkind → unkindness. Sometimes un- in an adjective corresponds to in- in the noun because the noun is based on a Latin stem rather than the English word with un-: unequal → inequality. Check each pair in a dictionary instead of adding a suffix at random.

A negative noun expresses a lack or an opposite property, not simply ‘absence’: dishonesty is a trait, while absence is the fact of something or someone not being present. Such a noun can readily become the subject: the dishonesty of the contractor delayed the project.

The subject of the adjective clause becomes the complement of an of-phrase, as in the safety of the vaccine, or a possessive modifier, as in the vaccine’s safety. An of-phrase is more natural for long or inanimate subjects, while a possessive often suits short or personal ones. Other clause frames can also be transformed: how + adjective, as in How safe the vaccine is → the safety of the vaccine; so + adjective + that, as in so dense that few finished it → the sheer density of the text meant that few finished it; and it is + adjective + to-infinitive, as in It is necessary to document every decision → the necessity of documenting every decision.

Integrate the new noun phrase into a sentence through a predicate. For example, The text was so dense that few finished it → The density of the text meant that few finished it. The causal relationship is preserved here. The new verb does not have to be a linking verb such as be.

When an adverb previously modified a quality but must now modify a noun directly, the corresponding adjective is often needed: strikingly similar → striking similarity; increasingly dependent → increasing dependence. In increasingly dependence, the adverb has incorrectly been placed where an adjective belongs. Not every adverb in the sentence needs changing: what matters is the word it modifies.

Choose a natural combination with the new noun: very likely → high likelihood; very important → of great importance; extremely cautious → extreme caution. Not every pair can be formed mechanically: the choice of high, great, strong or another adjective depends on the noun. The findings are of great importance means that the findings are very important.

The adjective’s complement carries over, but not always unchanged: conscious of → consciousness of, able to → ability to, sensitive to → sensitivity to, dependent on → dependence on, responsible for → responsibility for. Sometimes the frame changes: different from → difference between, likely to → likelihood of + -ing, important to + infinitive → importance of + -ing. Possibility, likelihood and certainty can take a that-clause: the possibility that talks will fail.

The article depends on meaning and context. The importance of sleep names the particular property under discussion, but an of-phrase does not itself require the: Freedom of speech matters; Availability of water varies. Abstract nouns are often uncountable, and some also have countable meanings: a kindness is a kind act, and a difficulty is an individual problem. Check the usage of the particular word.

The noun phrase the volatility of the market is not a complete sentence on its own. It can be integrated as a subject or object: The volatility of the market worries investors. The predicate must convey the intended relationship, such as a cause, consequence or reaction.

A noun with this or that can summarise the previous idea: Border crossings remain unpredictable. This unpredictability raises costs for exporters. The reader sees which property is being discussed next. Avoid excessively long chains of nouns, but the number of verbs or clauses is not limited to one: this is a matter of clarity, not a grammatical prohibition.

Nominalisation is a choice associated with academic register, not a correction of an error: Experts doubted that the data were reliable remains perfectly good English. Dense sequences of nouns make a text harder to read, especially when the agent disappears. If the reader is not a specialist and an adjective is natural, consider keeping it. The test is whether the reader quickly understands what the sentence concerns and who or what is responsible for the situation.

This rule does not cover nouns derived from verbs, such as introduce → introduction, or chains of nested nominalisations. Nor does it cover nominal uses of adjectives such as the poor and the elderly, where the adjective appears without a suffix and denotes a group of people. Not every adjective has a convenient noun: the size of is more natural than uncommon bigness, and the height of is more natural than tallness.