Showing what would happen if your computer's spell check became sentient and snarkily judgmental, whoever runs Merriam-Webster's Twitter account has taken US President Donald Trump to task for a social media spelling error. Again.

It started sometime after 4pm on Saturday, at the end of a mostly peaceful protest in Boston, where most demonstrators rallied against hate.

Tweets gone wrong:US President Donald Trump. Credit:AP

Afterwards, the President thumbed out a tweet of solidarity.

"Our country has been divided for decades," he tweeted. "Sometimes you need protest in order to heel, & we will heel, & be stronger than ever before."