theatin

from The Century Dictionary.

• Of or pertaining to the Theatins.
• noun One of a monastic order of regular clerks founded at Rome in 1524, principally by the archbishop of Chieti in Italy, with the purpose of combating the Reformation.

from the GNU version of the Collaborative International Dictionary of English.

• noun (R. C. Ch.) One of an order of Italian monks, established in 1524, expressly to oppose Reformation, and to raise the tone of piety among Roman Catholics. They hold no property, nor do they beg, but depend on what Providence sends. Their chief employment is preaching and giving religious instruction.
• noun (R. C. Ch.) One of an order of nuns founded by Ursula Benincasa, who died in 1618.