unreliable 

undependable, irresponsible, untrustworthy

James : Andy has bailed again he is now on punishment
Nick : You know baldy he is unreliable

unreliable by yittybum June 30, 2011

Unreliable, untestable truth

The embodiment of faith.

Oh, you have faith do you?

The next time you feel compelled to use the word 'faith', why don't you try replacing it with: 'pretending to know something that I really don't know''.
If you really want to keep it simple you could just say: 'I have unreliable, untestable truth'.

Unreliable, untestable truth by YAWA October 31, 2017

Unreliable texter 

A person who texts unreliably; they can either respond in ten minutes or ten days. Also quality of texts are unpredictable. They are either short one words or paragraphs.

Oh yeah you know Courtney? She’s such an unreliable texter! She hasn’t responded in a week!

Unreliable texter by CTwister February 2, 2023

Unreliable 

Not able to be counted on; Not performing expected duties.

UrbanDictionary.com's definiton of pippie is very unreliable, as each one of the six definitons gives a different meaning for the word.

Unreliable by Rodney Basil April 10, 2004

Unreliable Narrator

When in a story, the voice that speaks to the audience purposely misleads them to better position them for a surprise, double cross, or twistaroni

dude from fight club was an unreliable Narrator, much like whoever wrote this example

Unreliable Narrator by theoneandonlyzenkenone December 7, 2021

Unreliable 

Omar Almi

Omar is always unreliable because he never gets online at time we agreed on

Unreliable by That one Arab kid December 31, 2022

Unreliable Source 

Unreliable Source is a common tag used by Wikipedia. Wikipedia is (or intended to be) a open source encyclopedia.

In theory, the tag "Unreliable source" is used when an article or part of a article cite or talk about some questionable content.

But, in a real world scenario, "Unreliable source" is used as a form to piss off contributors. Even by using logic, if a statement is correct but some editor consider to screw it, then it can claim that the statement is incorrect.

Writer-"The roses are red"
Editor -I put a unreliable source tag because the statement does not cite any source claiming it.
Writer-But i put not only a source but 3 sources.
Editor -Sorry about that but *im* still consider unreliable.

Unreliable Source by magallanes June 24, 2010