the opposite of cosign. whereas to cosign is to agree or support someone or their actions, to nosign is to disagree with someone or frown upon their actions. this word can be used by itself in reply to something (example 1), as a noun (example 2), or as a verb (example 3).
Justin Bieber/Shawty Mane: speaking in tongues, yabababfreiufher...
Other Person: NOSIGN.
Kanye West: i replaced my whole set of bottom teeth with diamonds and gold.
Other Person: that gets a nosign from me.
Person: hey, Other Person! i just found out that Justin Bieber made a rap video under the name Shawty Mane, and that Kanye West replaced his whole set of bottom teeth with diamonds and gold.
Other Person: i refuse to cosign either of their bullshit. in fact, i'm going to go so far as to nosign their bullshit.