nayslayer 

One that is capable of completely obliterating someone's doubts or beliefs.

After numerous individuals and organizations voiced their doubts, concerns, and slanderous posts about the prospects of the new business opening up successfully, the nayslayers packed the house so full on opening night a line started forming outside the door.

nayslayer by flashback June 4, 2013

Nayslayer 

Someone who refuses to take no for an answer. The slay every nay (no). An archenemy of the creative michelangeNo.

Stop being such a nayslayer and leave me in peace.

No matter how much John said no, Phil had got nayslaying down to an art. John gave in.

Nayslayer by Logoasaurous September 8, 2021

naysayer 

One who frequently engages in excessive complaining, negative banter and/or a genuinely poor and downbeat attitude. Naysayers are distinguished by their tendency to consistently view the glass half empty, make frequent one-way trips to negative town, and constantly emphasize the worst of a situation. They have the capacity to rant and whine for hours on end about the most insignificant inconveniences. They tend to travel solo, but have the keen ability to spread their pessimistic attitude to a group of unsuspecting bystanders and encourage others to employ their mindset.
Naysayers tend to blend in with those around them rather well, granted they have learned over the years to adapt to their surroundings. However, when the opportunity arises, their true nature will be exposed and they will stop at nothing to exclude others or bring a general sense of negativity to any situation.
Not to be confused with non-naysayers who fight against the negativity brought forth by naysayers, make the best of a situation and are not afraid to call out a naysayer on the spot.

Being the world renowned naysayer that he was, Jobe complained about nearly every aspect of the party and made sure nobody else had a good time.

naysayer by non-naysayer September 10, 2008

Naysayer Bullshit Statistic 

The law known as the "Naysayer Bullshit Statistic" means that at least 50% of people with a highly negative view of something are poorly informed about it, haven't tried it to its full potential or are just plain making stuff up to satisfy their bias opinion regardless of whether they know they're wrong or not.

Person who hasn't tried Stereo-3D: "3D is a fad"

Person with common sense: "You sir, fall into the Naysayer Bullshit Statistic"

Naysayer Bullshit Statistic by something2someone August 26, 2010

professional naysayer 

A person whose sole function in an organization is to point out flaws in recommended plans and approaches. This person never provides reasonable insights of their own volition rather just point out flaws of other ideas.

In the meeting yesterday we had several good ideas but Fred continued in his role as professional naysayer pointing out flaws while never offering any useful advice or ideas of his own.

professional naysayer by FPB September 29, 2010

naysayer 

someone with an aggressively negative attitude

I have to avoid him because he's just a naysayer. He drains my batteries.

naysayer by Tobias January 9, 2004

sayslayer 

A singer, especially one performing a rendition of another artist's song, who completely destroys the lyrics by inserting far too many "I said"s in front of the original lyrics, thus abusing the emphatic tag, especially at the beginning of the song where the lyrics were not actually previously said yet.

original Aretha Franklin lyrics:
I don't want nobody, always
Sittin' around me and my man...

The sayslayer's version:
I said I don't want nobody,
I said always sittin' around
a-me and my man...

sayslayer by Webspin October 11, 2007