All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.
According to the Global Arabic Encyclopedia, khaaniqaah is a building designed specifically for accommodating the gatherings of the Sufis and those who seek retreat for worship. It was known in the Ottoman reign as takiyyah (pl. takaaya).
The Sufi religious practices are a mixture of correct and incorrect practices, like with many other religious sects affiliated to Islam; the correct practices are to be accepted and the incorrect ones should be rejected. However, most of the present-day Sufi doctrines are corrupted, most of their ideas are deviated, and most of their devotional practices and thikr (remembrance of Allaah) are mere religious innovations and the like of aspects of violations of the Quran and Sunnah. For more information about Sufism, please refer to fataawa 29243 and 82017.
Allaah knows best.