Jamaati is an Urdu adjective derived from the name of the South Asian religio-political party named Jamaat-e-Islami, which has wings in Pakistan, India and Bangladesh.
A 'Jamaati' is a supporter and member of the Jamaat-e-Islami, the Islami Jamiat-e-Talaba, or the Islami Jamiat-e-Taalibaat.
This word is also sometimes used as an adjective or noun for people who are politically sympathetic to the point of view of these groups/parties and the political thought of Sayyid Abul Ala Maududi. It is often, incorrectly, used for other conservative Muslims, such as members of the Tablighi Jamaat.