BDB9054
שְׁרִירוּת, usually שְׁרִרות noun feminine firmness, always = stubbornness; only construct ׳ שׁ, followed by ׃לֵב : Jer 9:13; Jer 13:10; Jer 23:17; Deut 29:18; Ps 81:13 (שְׁרִירוּת); לִָ ם הָרָע ׳ שׁ Jer 3:17; Jer 7:24; Jer 11:8 (׳ שְׁרִי), so (לִבּוֺ) Jer 16:12; Jer 18:12.