Simple Definition of sinister

from our Learner's Dictionary

sinister

adjective

ˈsɪnəstɚ How to pronounce sinister (audio)
: having an evil appearance : looking likely to cause something bad, harmful, or dangerous to happen
There was something sinister about him.
He looked sinister.
sinister black clouds

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“Sinister.” Merriam-Webster.com Simple Definition, Merriam-Webster, https://www.merriam-webster.com/simple/sinister. Accessed 21 Jun. 2026.

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