Use a hyphen when you join two words to form an adjective. This eliminates confusion.

  • first-year course
  • full-time equivalent
  • third-year students
  • part-time studies
  • the government-mandated budget cut

Use no hyphen when the meaning is clear and there is no ambiguity.

  • one half course
  • a full course
  • one half of the students

Never use a hyphen where an "ly" adverb modifies an adjective:

  • fully grown cat
  • barely readable document

A hyphen should not be used to join a prefix to a root/base except to avoid doubling a vowel, tripling a consonant, duplicating a prefix or when the context is confusing or causes ambiguity.

  • anticlimax (a familiar term, requiring no hyphen)
  • antibiotic


  • anti-inflation
  • anti-junta
  • anti-ageism
  • anti-racism
  • anti-Semitic

Use a hyphen with the prefix "re" where the word would otherwise be confusing.

  • re-admission
  • re-entry
  • re-coiled the rope (as opposed to recoiled in horror)
  • re-covered a chair (as opposed to recovered from an illness)