You carefully selected Search Keywords to run ads that your customers put into Google Search.

However, Google runs ads for additional words they decide are "related" to your chosen Keywords.
Google makes more money when advertisers run many Keywords, even when some of them don't don't make you money.

Here's how to stop running ads for search words that waste most of your budget,

Go to your Google Search Ads Campaign
Looking at your Search Campaign, click Insights and reports in the left column, then click Search Terms in the dropdown menu.

Now you see a list of words that people actually put into Google Search when Google ran your ad for the timeframe you selected.
Click on the Clicks Column to see which words had the most clicks in descending order.
Make a list of SINGLE WORDS that people who don't buy your product put into Google Search.

Add these single words as Negative Keywords, so Google stops running ads for them.

Go to the left Column where you selected Search Terms,
Use the side scroll bar on the right side to scroll down to Audiences, Keywords and content.
Click Keywords in the dropdown menu.
On the Keywords page, click Negative Keywords to the right of Keywords.
Click + BLUE CIRCLE to add Negative Keywords
To each line, add SINGLE Negative Keywords with double quotes around it (Phrase Match) at the Campaign level (not Account Level).
Click SAVE --- make sure each line has only ONE WORD and that it's Phrase Match.

Adding Negative Keywords makes you serious money, and it doesn't take much time.

See The Google Search Ads Guide sections SEARCH TERMS and NEGATIVE KEYWORDS for step-by-step screenshots and strategies at www.RichBruns.com