Do not use the hyphen:
1. When writing points of the compass: e.g., northeast, southwest; but north-northeast, etc.
2. In words ending in like, unless compounded with nouns containing more than one syllable (except when ending in l): e.g., childlike, lifelike; but business-like, bell-like, etc.
3. In compounds ending with man or woman: e.g., workman, needlewoman, etc.
4. In phrases such as by and by, by the bye, good morning, attorney at law, coat of arms, etc.
5. In words ending in boat, house, look, room, side, yard, shop, mill, field, work, chair, maker, holder, keeper, skin, store, book, fold, score, penny, pence when the prefixed noun {50} contains but a single syllable: e.g., twofold, schoolroom, handbook, windmill, bookkeeper, workshop, etc. Exceptions: Court-house and State House.
When prefixed noun contains two syllables, use the hyphen: e.g., bucket-shop, twenty-fold, ante-room, mason-work, paper-mill, etc.[9]
When prefixed noun contains three or more syllables write as two separate words: e.g., policy shop.
6. In compounds of bi, tri, semi, or demi: e.g., bimonthly, tricolor, semiannual, demijohn. Exceptions: long or unusual formations: e.g., bi-centennial, etc.
7. In today,[10] tonight, tomorrow, viewpoint, or standpoint.
[10] Cf. the old English words to-morn, to-year, etc.
8. In connection with the negative prefixes un, in, and a: e.g., unrepublican, inanimate, etc., but the prefix non requires the hyphen except in words which have become common: e.g., non-conductor, but nonsense.
9. In connection with the words over and under employed as prefixes: e.g., overestimate, undersecretary; but over-soul, over-spiritual, under-man.
10. In connection with the Latin prepositions ante, anti, inter, intra, post, sub, and super: e.g., antedate, antidote, subtitle, etc.; but ante-room, anti-imperialistic, intra-atomic. {51}
11. In spelling out a series of fractions: e.g., I can secure you one, two, or three fifths, not one-, two-, or three-fifths.
Nor in writing ordinary fractions: e.g., one half, five eighths, etc.
But another class of fractions require the hyphen: e.g., twenty-fifth, twenty-two one-hundredths.
12. In compounds ending with holder or monger: e.g., stockholder, ironmonger.
13. In compounds beginning with eye: e.g., eyeglass, eyebrow, eyelash, eyewitness, etc.
14. In compounds with the word school: e.g., schoolmates, schoolmaster, etc. Exceptions: when made with a participle: e.g., school-teaching; or in combinations where separate words are more clear: e.g., school committee, school children, etc.
15. In compounds with deutero, electro, pseudo, sulpho, thermo, etc., unless the compound is unusual: e.g., electrotype, pseudonym, etc.
16. In compound adverbs: e.g., meantime, moreover, forever, everywhere, etc. But in phrases like after a while, in the mean time, for ever and ever, the words should be separated.
17. In words like anybody, anyhow, anything, anyway, anywhere, somebody, somehow, something, sometime, somewhat, somewhere. But any one and some one are written as separate words.
{52}