Google “bolds” words in ad text that match the keywords you’re bidding on. The example below shows that synonyms of keywords are now appearing in boldface.

Searchengineland.com confirmed with Google that this is a new “feature,” and it also works with antonyms. So, for example, if the keyword is “GM,” and the words “General Motors” are included in the ad, then “General Motors” will appear in boldface.