What does respondent enters a general denial mean

It means that the respondent denies every allegation in the complaint. This suggests that they are ready to go to trial, and require the petitioner to prove the allegations made in the complaint. The respondent will likely present evidence to contradict the claims made.

It just means that all of the allegations in the Petitioner that you filed are denied and that the Respondent is going to make you have to prove all of the allegation in the divorce proceeding. Definitely not uncommon in civil cases. A little more unusual in divorce cases. Normally, parties will at least admit that they were married, have children, etc.