chāū- [short prefixal form of चार] four-, as in चौकन्ना lit. four eared; चौकोर lit. having four sides; चौखट lit having four woods; चौगुना four times; चौमंज़िला four-storeyed; चौरस्ता lit. having four paths.

chāūkannā a [lit.] all ears, alert, vigilant; ~ कुत्ता alert dog; चौकन्‍न कान alert ears; चौकन्‍नी आँखें vigilant eyes. ~ करना to alert; ~ रहना to be alert/vigilant: चोर ~ हो गया the thief became alert; पुलिस ने हमें ~ कर दिया the police alerted us. [syn. सावधान, चौकस]