Using hyphens with prefixes and suffixes

Most words containing prefixes or suffixes are written without hyphens: antiwar, Romanesque. Here are some exceptions:

BEFORE CAPITALIZED BASE WORDS un-American, non-Catholic
WITH FIGURES pre-1960, post-1945
WITH CERTAIN PREFIXES AND SUFFIXES all-state, ex-partner, self-possessed, quasi-legislative, mayor-elect, fifty-odd
WITH COMPOUND BASE WORDS pre-high school, post-cold war
FOR CLARITY OR EASE OF READING re-cover, anti-inflation, un-ionized

Re-cover means “cover again”; the hyphen distinguishes it from recover, meaning “get well.” In anti-inflation and un-ionized, the hyphens separate confusing clusters of vowels and consonants.