1
medical
: a serious mental illness that causes you to falsely believe that other people are trying to harm you
She was diagnosed with delusional paranoia.
2
: an unreasonable feeling that people are trying to harm you, do not like you, etc.
I had to admit that my fears were just paranoia.
Cite this Entry
“Paranoia.” Merriam-Webster.com Simple Definition, Merriam-Webster, https://www.merriam-webster.com/simple/paranoia. Accessed 22 Jun. 2026.
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