1)To believe something that is different from the facts.
1) Roberto Martinez is delusional to believe he is a EPL manager.
2) Roberto Martinez is delusional by saying "Over the last three years we (Everton) haven't invested any money." (23 Apr 2016)

The transfer records roughly show an outgoing of £82,630,000 and an incoming of £49,500,000 equating to a expenditure of over £30,000,000.

*Other commonly used words to describe him are "charlatan", "deranged", "arrogant", "stubborn", and "fullofshit".
by RMandBkGTFO April 23, 2016
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To have a misconception.
Wife: (to rabbit) Sir, will you kindly show us the way to Littleton?
Husband: Um, rabbits don't understand English.

5-year-olds are delusional.
by frabrizio February 3, 2017
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1. The state of having a false opinion or belief.

2. Used to describe someone attached, possibly obbsessed, with an idea which is either false, or has changed. Synonymous to "living in the past."
Shannon really thinks she could get him back even though its clear there is no way of that EVER happening?!... She's delusional.
by MeowMeoow October 9, 2010
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An insult/label often flung at those who have beliefs that are not commonly accepted.
Person 1: I believe aliens are visiting Earth.

Person 2: OMG UR DELUSIONAL

Person 1: No I am not, I've thought about the issue thoroughly

Person 2: DELUSIONAL DELUSIONAL DELUSIONAL IM GONNA HAV U LOKD UP
by Shadow Creator March 21, 2008
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A person who is a Harry/Hermione shipper. They are easily upset, have a limited sense of humour, and do not read particularly well. In their spare time, they like to look for overly used symbolism where none exists. This term was coined by a most wonderful webmaster.
TeenyBopper1892!!: i ship Harry/Hermione. There so kaute and SO canon!!!!1!!!
HeronShipper: A delusional has entered the room, folks.
by Tiffi October 17, 2005
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when someone (usually a woman) has a false or highly exaggerated opinion of themselves.
Lisa thinks she is a princess. She is in fact delusional
by Ronald McD February 10, 2012
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Believing something to be true that is clearly not. Someone who is not thinking clearly. Used to describe someone attached to an idea which is obviously false.
Hugh believes that Tottenham are a bigger club then Arsenal. He's delusional.
by Truelondon December 18, 2018
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