This post discusses two categories of parts and speech key to helping writers describe things and actions.
An adjective is a word or a combination of two or more words that modify or provide additional information about a noun. There are three general uses of adjectives: attributive, predicate, and nominal.
An attributive adjective generally precedes the noun it modifies, as with broken in “a broken heart.” (One type of attributive adjective is a noun adjunct, a noun that functions as an adjective when it modifies another noun, as with kitchen in “kitchen counter.”) However, the noun may precede the adjective in the case of a postpositive adjective (also called a postnominal adjective), which occurs when the adjective is itself modified by an adverbial phrase, as in “a heart broken for the last time” and in phrases borrowed from other languages (such as “heir apparent”) and archaic or poetic usage (as in “forest primeval”).
A predicate adjective is connected to a preceding noun by a linking verb, as with curious in “children are curious,” and a nominal adjective is one that functions as a noun substitute. This may occur in reference to a collective group when the noun is implied, as in “the wealthy,” or in the case of a superlative such as “the biggest,” or when a noun is elided rather than repeated (“I’ll wear the red shirt, and you wear the green”).
Determiners are a category of words formerly considered by linguists as adjectives but now classified as a distinct part of speech, though dictionaries still identify them as a type of adjective. Examples of determiners that resemble adjectives in use include demonstrative determiners such as this and that, distributive determiners such as each and any, interrogative determiners such as what and which, possessive determiners such as my and their, quantifying determiners such as few and many, and numbers.
Phrasal adjectives, modifying phrases that precede or follow a noun, are usually hyphenated, when they precede the noun, to emphasize their combination, as in “hardest-working employee,” but not when they follow (“the employee who is the hardest working”). Exceptions are made for permanent phrasal adjectives (such as cost-effective) that appear in the dictionary; these retain hyphenation after a noun. (Also, adjectival compounds beginning with self, such as self-respecting, are always hyphenated.) Likewise, omit hyphens in standing phrasal adjectives such as “post office” that are not hyphenated in their dictionary entries (“post office employee”).
A source of hyphenation error is when a noun phrase that often appears as a phrasal adjective, such as “long term,” is hyphenated. Hyphenation is correct in a phrasal adjective before a noun (“a long-term plan”), but such a term is open not only after a noun (“a plan that is long term”) but also in isolation as a noun phrase (“in the long term”).
Also, take care with comparative and superlative adjectives used in phrases such as “more punitive measures.” When “more punitive” is not hyphenated, more means “additional.” However, when a hyphen is employed, the phrase means “punitive to a greater degree.”
Phrasal adjectives may include more than two words, as in “happy-go-lucky attitude,” but strings of more than three words are inadvisable, especially when they consist of a train of nouns employed as adjectives, such as in “data leakage prevention strategy.” Technically, the first three words, which together modify strategy, should be hyphenated (“data-leakage-prevention strategy”) to aid in reader comprehension (otherwise, the reader may not recognize the intended relationship until the last word is reached and may have to backtrack to understand the phrase), but such usage is cumbersome; it is often better to rephrase the term (for example, “strategy to prevent data leakage”).
An adverb is a word that modifies a verb or another part of speech to describe what, when, where, why, or how an action occurs; adverbial phrases and adverbial clauses also perform this function. The term adverb most familiarly applies to words ending in -ly that without the suffix serve as adjectives, such as lively, as in “They watched the lively performance.” However, many adverbs lack the suffix, as when they refer to location (for example, up or there), time (soon or today), frequency (seldom or daily), and so on.
In addition, adverbs may be flat, meaning that they are root forms of -ly adverbs. These often appear on their own in informal contexts (as with quick in “Run quick to the store”) but may also appear in adverbial phrases, as in “quick-acting compound.” (Note that adverbial phrases are distinguished from phrasal adjectives in that they usually do not include hyphens—hyphenation in such phrases as “privately held” is erroneous. Those with flat adverbs are an exception.)
Adverbs also modify parts of speech other than verbs. For example, in “quite annoying,” the adverb quite modifies the adjective annoying, and in “very quietly,” one adverb modifies another. The adverb only may modify a noun (“She drinks water only”), and adverbs modify prepositional phrases (in “I was almost up the stairs,” almost modifies not was but “up the stairs”) and clauses or even entire sentences (as in the case of actually in “Actually, they are on their way now”).
Adverbs that modify an entire sentence rather than a verb or another part of speech are called sentence adverbs. Often, they begin a sentence, as actually does in the example in the previous sentence, or as often does in this sentence you are reading, though they may appear in the midst of a sentence or, as a tag following a comma (or, sometimes, a dash) at the end of a sentence. Many sentence adverbs, such as clearly, fortunately, and regrettably, signal that the sentence represents the writer’s opinion or at least conveys a bias.