Harassment is a description, not always a claim
New York courts generally do not recognize a freestanding civil claim simply called harassment. A lawsuit has to fit a recognized legal theory, and which one depends on where the conduct happened and why. At work, the strongest path is usually discrimination law, because harassment tied to sex, race, disability, religion, or another protected characteristic is treated as discrimination under federal, state, and city law. Conduct that follows a complaint you made can support a retaliation claim. Outside work, depending on the facts, a claim may be framed as defamation, intentional infliction of emotional distress, or under a narrow statute such as one covering intimate images, and the requirements are demanding. Some behavior is also a crime, and the criminal process runs separately from any lawsuit.
When a court case is not the first step
If you fear for your safety, an order of protection may matter more than a damages case; Family Court handles these only between relatives or intimate partners, and otherwise one usually comes through a criminal case. For workplace conduct, the employer's internal complaint process and an agency charge are often part of the path, and how you used them can affect the claim later. Keep the messages, voicemails, and posts themselves, not just descriptions of them, and keep a record of any report you made to police, a manager, or a platform. Do not respond to the person to confront them or to gather more evidence; let your lawyer decide how contact is handled.
What we look at first
We start by identifying who is responsible: the individual, an employer that knew or should have known and did not act, or both. Then we look at which legal theory fits the facts and which deadlines apply, since some claims, such as defamation, have short limitation periods in New York. We talk about what you want: the conduct to stop, a change at work, compensation, or some combination, because those goals can point to different procedures. Bring whatever you have saved, the names of anyone who witnessed the conduct, and any earlier complaints and responses.