This means something to drink, a drink of something. ñi jahēña would be the change of something into a drink or to make a drink of something, or more simply, to drink.
te macēna mahēna anīλīkimma antanīsi ānen anāste ñe marōāñēl;
There was an old woman with clothes decorated with black things like an oracle.
ē ñi marōāñēl rā sāen ē temme jatēmmēr ien ñarra jahēña tō jatarūna jawēha anhāri wē;
She came to him and called to him, “Do not drink the mirage water.”