The teenager has been touring the world rallying support for her green movement and calling for young people to hold their governments to account over their contribution to climate change.
However Greta caused anger and confusion at a rally in the Italian city of Turin on Friday after she told activists “World leaders are still trying to run away from their responsibilities but we have to make sure they cannot do that.
“We will make sure that we put them against the wall and they will have to do their job to protect our futures”.
The comment was quickly picked in right-wing circles which have frequently criticised the teenager, including far-right online publication Breitbart accused Greta of going “full Fidel-Castro”.
However the 16-year-old said the matter was simply one of translation – and that she had muddled a Swedish term with English words to come up with a ‘Swenglish’ cross.
“Yesterday I said we must hold our leaders accountable and unfortunately said “put them against the wall”. She wrote on Twitter. “That’s Swenglish: “att ställa någon mot väggen” (to put someone against the wall) means to hold someone accountable.
“That’s what happens when you improvise speeches in a second language. But of course I apologise if anyone misunderstood this. I cannot enough express the fact that I - as well as the entire school strike movement- are against any possible form of violence.
“It goes without saying but I say it anyway”.
It comes as the activist looks to head home for a break from campaigning after travelling the world by boat and rail.
Greta, who refuses to fly, arrived in Turin by train from Madrid after attending the UN climate summit in the Spanish capital. Those talks were originally intended to take place in Chile, only to be relocated following the outbreak of protests in Santiago.
The teenager spent much of the autumn campaigning in the US, memorably haranguing heads of state at the UN headquarters in September for their complacency and inaction over the environmental crisis.