A unitard is a single garment closely covering the body from at least the shoulders to the thighs. Some unitards also cover down to the feet (sometimes with foot straps) and have long sleeves, so cover the arms. Initially designed for sports, it is used by ballet dancers, acrobats, swimmers, wrestlers etc. but can also be worn as lingerie.
A 'complete body unitard' would normally have gloves, socks and a head hood (not always covering the face) included with the one-piece garment.