It's official:  MOTLEY CRUE singer VINCE NEIL has been charged with domestic violence and disorderly conduct.  Vince allegedly POKED and threatened his ex-girlfriend Alicia Jacobs and two of her friends in Las Vegas last month.

Police say Vince forced his way up to them... and, quote, "poked [them] with his right index finger... each time stating the words, '(eff) you.'"  Alicia told the cops she was "forcefully poked in her right shoulder blade."

Vince insists he's not guilty, and his lawyer says he will fight the charges.

(TMZ has a picture of Alicia's alleged post-poking bruise.  Here it is.)