An answer is a civil pleading made in response to a plaintiff’s complaint
In civil cases, the Complaint is a legal pleading drafted by a plaintiff and filed and served on the defendant. If the defense fails to file and serve their Answer within 30 days of having been legally served with the plaintiff’s Complaint, the defense will be in default, and all of the defendant’s defenses, objections, and denials will be deemed legally waived.
In most jurisdictions, the defense is allowed to answer the Complaint with what is called a general denial, which denies all of the plaintiff’s allegations and claims. The Answer will likely include affirmative defenses to the plaintiff’s allegations and claims.
The defense can respond with a Complaint of their own against the plaintiff. This is called a Cross-Complaint, and when filed and served on the plaintiff, will obligate the plaintiff to respond with its Cross-Answer to the defendant’s Cross-Complaint.