The trend in modern writing is away from using hyphens with prefixes and suffixes. For prefixes, the general rule is not to use a hyphen when combining with a word starting with a consonant (bypass, for example). Do use a hyphen if the prefix ends in a vowel and the word it’s combined with begins with the same vowel (pre-empt; but cooperate, coordinate). Also use a hyphen if the word following the prefix is capitalized (anti-Nixon), or to join doubled prefixes (sub-subparagraph). Guidelines for specific prefixes and suffixes follow.

co-

Use a hyphen when forming a word that indicates occupation or status (co-host, co-worker); otherwise, use no hyphen (coexist, coed).

-elect

Always use a hyphen with this suffix: President-elect Jim Miller.

ex-

Do not use a hyphen if it means out of (excommunicate, for example). Do use a hyphen if it means former (ex-wife, ex-president).

great-

Always hyphenate: great-grandfather.

-like

Do not use a hyphen unless the letter L would be tripled or the first word is a proper noun: businesslike, bell-like, Rastafarian-like.

mid-

Do not use a hyphen unless followed by a capitalized word: midterm, mid-American.

mini-

No hyphen: miniskirt, minivan.

non-

Do not use a hyphen unless it is followed by a proper noun or if the combination is awkward: nonjudgmental, non-nuclear, non-British.

over-

No hyphen: overextend, overrate.

pro-

Use a hyphen when indicating support for something: pro-chocolate. Otherwise, do not use a hyphen: pronoun, prorate.

self-

Always use a hyphen: self-important, self-defense.

semi-

Do not use a hyphen unless the word it is being combined with begins with an I: semisweet, semi-ignorant.

super-

Do not use a hyphen unless the word it is combined with is capitalized: superpower, super-Democrat. EXCEPTION: Super Bowl.

ultra-

No hyphen: ultraright, ultraviolet.

under-

No hyphen: underdog, underground.

-up

For nouns or adjectives, consult a dictionary, but here are some common examples: breakup, checkup, cover-up, follow-up, grown-up, holdup, makeup, mix-up, pileup, push-up, runner-up, shake-up, warm-up (also warm-down). As verbs, spell as two words.

• What time does warm-up start?
• I never warm up much.

up-

No hyphen: uptown, upstairs.

vice

Use as two words: vice president, vice chair.

-wide

No hyphen: nationwide, worldwide.

wide-

Usually hyphenated: wide-awake, wide-open. EXCEPTION: widespread.