Use the AND NOT connector to find documents in which a search word or phrase is to be excluded.
For example, the following search finds documents where the words "capital allowance" occur but the word "property" does not.
capital allowance AND NOT property
Because the exclusion covers the entire document, a document would be excluded if the word "property" appears anywhere in the document.
If you include AND NOT in your search, it should be the last connector you use. Otherwise it may produce undesired results.