“Impeachment” is another no-no. In December 2018, few companies blocked that word. A year later, nearly 50 companies had done so.

Some brand executives have told ad agencies that they are afraid of alienating customers or drawing the wrath of the presidential Twitter account.

“It’s a divided world that we live in,” said Raja Rajamannar, the chief marketing officer at Mastercard. “Can you afford to exclude half of your audience?”

Other companies are avoiding politically engaged ads out of simple fatigue.

“Trump has been in America’s 24-hour news cycle for the past four years: countless hours of ‘Saturday Night Live’ skits, tweets, memes, #resistance microsites, etc.,” Zachary Roif, an associate creative director at the marketing agency R/GA, said in an email. “People have simply had enough — enough outrage, enough disdain, enough shock value to the point where making a statement feels a little tired.”

And then there is the risk of offending Mr. Trump and how that could affect business.

“This notion that you pick on a president and then he tweets about you and is mean to your company is a new thing,” said Eamonn Store, the chief executive of the consulting firm FairShare and a former North American chief executive of Guardian News & Media. “If you happen to be a large technology brand like Microsoft, and the government is your biggest client, then the last thing you need is to be in conflict with the White House.”

Many companies, Mr. Store added, believe Mr. Trump will win re-election. If that happens, he said, “being the pro-impeachment enterprise is not going to be good for business.”

The president has railed against Amazon, Google and Harley-Davidson. When Nike announced in 2018 that it had entered into a new marketing deal with the former N.F.L. quarterback Colin Kaepernick, who had angered the administration by kneeling during the national anthem to protest police brutality and racism, Mr. Trump said on Twitter, “Nike is getting absolutely killed with anger and boycotts.”