impī̆grĭtas (inp-), ātis, f. [impiger],
activity , indefatigableness : viri fortissimi fortitudinis, impigritatis, patientiae, Cic. Rep. 3, 28, 40 (ap. Non. 125, 22).
impigritās (inp-) ātis, f impiger, activity, indefatigableness . ...
An Elementary Latin Dictionary