A girl with whom one conducts a relationship over the Internet, often involving cybersex.
Internet girlfriends typically are bisexual and/or morbidly obese and/or have mental health problems such as schizophrenia.
The above is the truth, but with the anonymity of the Internet, Internet girlfriends are most likely charlatans and compulsive liars in the way they conduct their Internet relationships.
His Internet girlfriend
admitted to him one evening that she was very paranoid, extremely self conscious, and apparently schizophrenic.