Sanskrit ish (7)
According to Monier-Williams’ A Sanskrit-English Dictionary, Sanskrit word ish means “the refreshing waters of the sky, sap, strength, freshness, comfort, increase, good condition, and affluence.” It traces its origin to the Tamil root irumpu, and due to the ra > ya > ca phonetic change, irumpu transforms into ish in Sanskrit (irumpu > ish). The following words, related to Sanskrit ish, also originate from Tamil irumpu.
ishá, “possessing sap and strength; wellfed, strong; sappy, juicy, fertile.” ishá-vat, “vigorous.” isháyati, isháyate, “to be sappy; to be fresh or active or powerful.” ishayù, “fresh, strong, powerful.” ishirá, “refreshing, fresh; flourishing; vigorous, active, quick; name of Agni.”