Thesaurus Lookup

The Crossword Construction Kit comes with an English (U.S.) or English (U.K.) thesaurus. The version you want can be selected by clicking on Options | Preferences | Language. Select the thesaurus you prefer. Or select Choose at Thesaurus Use Time, which will prompt you for the preferred thesaurus at the time you create the puzzle.
 
The thesaurus is used while creating a new puzzle or modifying an existing one. Place the cursor on either the word or the clue and click on the Thesaurus button to open the Thesaurus Lookup window.

Create New Puzzle window > Thesaurus button
 

Looked Up

The word selected from the puzzle is inserted into this field. If you want to search on a different word, enter the new word in this edit field.

Suggest 
The Suggest button is primarily used if the word you are looking for is not found in the thesaurus. Clicking on the Suggest button opens the Word Suggestions window as shown below.  It supplies a quick list of possible words. Highlight a word from the list and click OK. The highlighted word replaces the original word in the Looked Up field of the Thesaurus Lookup window.

 
Look Up
If you want to find a synonym for another word besides the original word  entered, delete the original word in the Word field and replace it with another. Click on the Look Up button to display a new set of synonyms.

Replace Word

Select a word from the synonym or antonym list to place it in the Replace With field. Click the Replace Word button to replace the original Puzzle Word with the new word selected from the Thesaurus.

Replace Clue

Select a word from the synonym or antonym list to place it in the Replace With field. Click the Replace Clue button to replace the original Puzzle Clue with the new word selected from the Thesaurus. Use this option as a method to develop clues for words in the puzzle.

Cancel

Click Cancel to exit the Thesaurus without making any changes.

Meanings 
If the word has several distinct meanings, the various meanings will be displayed in this field. The highlighted word in the category list will display synonyms to the right in the Synonym field. Highlight another word in the Meanings list and another set of synonyms will appear from which you can select an appropriate clue.
 
Synonyms 
This is the list of words with similar meanings to the word displayed in the Word field. Highlight the synonym to be used and it is displayed in the Replace With field. Or double click on a synonym and it replaces the original word in the Word field.

 
Antonyms 
The antonym field displays words with opposite meanings to the word displayed in the Word field. You can highlight one of the words in the antonym list and a list of words with opposite meanings displays in the synonym list.