Renita Hill sued the former The Cosby Show star in October (15), claiming he drugged her drinks and molested her while she was passed out during their stint on the road together in the 1980s.

She went public with her story in a U.S. TV interview last year (14), as a string of other reported victims came forward with similar alleged experiences, but Cosby's attorneys slammed the various accusations and called the credibility of the women into question.

Hill fired back by filing suit for defamation in a Pennsylvania court, slamming the funnyman for attempting to ruin her reputation.

Now Cosby's attorneys have responded to the legal action by asking a judge to dismiss the case because it holds no merit, arguing Hill was never mentioned by name in the original statements of denial. They also claim that even if Hill was referred to in the statements, the comments were simply a matter of opinion and are therefore protected by constitutional law.

"Under well-founded precedent, statements of opinion, even if capable of causing embarrassment, can never serve as the basis for causes of action for defamation, false light and intentional infliction of emotional distress," read the court papers, which were filed on Friday (18Dec15).

The 78 year old is facing a number of defamation lawsuits and last week (ends18Dec15), he launched a countersuit in Massachusetts against a group of seven women who accused him of sexual misconduct, only to have their accusations shot down and their credibility questioned.

On Monday (21Dec15), Cosby also slapped his own defamation suit against former supermodel Beverly Johnson, who maintains he tried to drug her during an encounter in the 1980s. He is fighting back against the accusations, with his Los Angeles lawyers disputing Johnson's account as "false, malicious, opportunistic, and defamatory".

More than 50 women have gone public with decades-old claims of inappropriate behaviour against Cosby in the past 14 months. The TV star, who has never been charged with any crime related to the counts, has denied all accusations.