From charash in the sense of silence; quiet, i.e. Sultry (as feminine noun, the sirocco or hot east wind) -- vehement.
see HEBREW charash
[חֲרִישִׁי] adjective meaning wholly dubious; only חֲרִישְׁית קָדִים רוּחַ Jonah 4:8; a silent east wind is not suitable in context; still = sultry is mere conjecture; Hi autumnal (√ I. חרשׁ); St proposes חרישׂית = חריסית, from חֶרֶס sun (or √ whence חֶרֶס comes) hot east wind; We makes no attempt to explain.