2.04 Compound adjectives; adjectives and participles in compounds

(a) Hyphenate adjective-plus-noun and participle-plus-noun compounds modifying another noun, when ambiguity might otherwise result:

• cold-storage vaults
• crude-oil exporting countries
• large-scale development
• special-interest groups

When the compound is used predicatively, retain the hyphen only when the expression remains adjectival:

• The development was large-scale.
• His position is full-time.

but

• Development proceeded on a large scale.
• He works full time.

(b) Hyphenate compound adjectives made up of two adjectives that describe a colour without the suffix ish, whether they are placed before or after the noun. Hyphenate compounds with the suffix only when they precede the noun:

• It was covered with blue-green algae.
• It was blue-green.
• The leaves were bluish green.
• The tree had bluish-green leaves.

Do not hyphenate adjectives indicating a specific shade (even if they precede the noun):

• dark green paint
• a bright red dress
• strawberry blond hair

(c) Hyphenate adjective-plus-participle compounds, whether used before the noun or after it:

• an odd-sounding name
• The name was rather odd-sounding.
• a smooth-talking salesman
• The visitor was smooth-talking.

(d) Hyphenate compounds made up of an adjective plus a noun to which the ending ed has been added, in any position in the sentence:

• able-bodied
• many-sided
• short-handed
• strong-willed

(e) Hyphenate two-word compound adjectives consisting of a noun plus a gerund when they precede the noun:

• the decision-making process
• a problem-solving approach
• a profit-sharing plan
• a tape-recording session

See also 2.03 Nouns with adjectives and participles(c).

(f) Hyphenate compound adjectives whose final constituent is an adverb of direction or place (in, out, down, up, etc.) when they precede the noun:

• a built-up area
• a drive-by shooting
• all-out competition
• the trickle-down theory

(g) Hyphenate compound adjectives made up of a preposition and a noun:

• after-tax income
• in-service courses
• on a per-gram basis
• out-of-province benefits

(h) Hyphenate a compound adjective one of whose constituents is a finite verb:

• a pay-as-you-go approach
• a would-be writer

(i) Hyphenate phrases of more than two words, at least one of which is an adverb or preposition, used as attributive adjectives:

• the cost-of-living index
• a long-drawn-out affair
• a subject-by-subject analysis
• a work-to-rule campaign
• an up-to-date approach
• on-the-job training

(j) Do not hyphenate French or foreign words used as adjectives or in italics, proper nouns used as adjectives, or words in quotation marks:

• a Privy Council decision
• a New York State chartered bank
• a pure laine Quebecker
• a dolce far niente attitude
• a priori reasoning
• a "zero tolerance" approach

Note that this rule does not apply to French or foreign words no longer considered as such:

• avant-garde filmmaking
• a laissez-faire approach

(k) Do not hyphenate chemical terms used as adjectives:

• a calcium nitrate deposit
• a sodium chloride solution

(l) Hyphenate compound proper adjectives that form a true compound, but do not hyphenate those in which a proper adjective is combined with a simple modifier:

• Anglo-Saxon period
• Sino-Russian border
• Austro-Hungarian Empire
• Greco-Roman art
• Latin American governments
• Middle Eastern affairs
• North American interests
• Central Asian republics

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