The Marvel movie debuted on the streaming service on 25 December, with a synopsis reading: "Superheroes amass to stop intergalactic sociopath Thanos from acquiring a full set of Infinity Stones and wiping out half of all life in the universe."
Viewers complained on social media that the description was inaccurate.
"Really take issue with Netflix categorising Thanos as a sociopath," one person wrote. "He’s clearly not."
"Sorry, but Thanos is definitely not 'an intergalactic sociopath,'" someone else tweeted.
Sociopaths, according to the American Psychiatric Association, tend to show "a disregard for laws and social mores", "a disregard for the rights of others", "a failure to feel remorse or guilt", and "a tendency to display violent behaviours".
Those four traits are listed as commonalities displayed both by sociopaths and psychopaths. Additional behaviours listed as being characteristic of sociopaths include agitation and emotional outbursts.
A new description of Avengers: Infinity War later omitted the word "sociopath", indicating the streamer had amended its synopsis.
The new summary, according to a screenshot published by Comicbook.com, reads: "Invader. Annihilator. So-called saviour.
"As Thanos moves ever closer to omnipotence, the fate of the universe rests with the Avengers."
This new description might not be showing up for all Netflix users at the moment and can still vary among accounts.
The Independent has reached out to Netflix for more information.
Avengers: Infinity War, starring a long list of Marvel stars including Robert Downey Jr, Chris Hemsworth, Mark Ruffalo, Chris Evans, Scarlett Johansson, Benedict Cumberbatch, Tom Holland, and Chadwick Boseman, came out in April 2018.
Its sequel, Avengers: Endgame, is scheduled for April 2019.
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