If, during a spell check, InDesign displays an unfamiliar word in the Check Spelling dialog box, select the dictionary from the Add To menu, and then click Add. You can also use the Dictionary dialog box to give you more control over how words are added to an exception word list.
Type one tilde (~) to indicate the best possible hyphenation points, or the only acceptable hyphenation point, in the word.
Type two tildes (~~) to indicate your second choice.
Type three tildes (~~~) to indicate a poor but acceptable hyphenation point.
If you want the word never to be hyphenated, type a tilde before its first letter.