Or tsmithuth {tsem-ee-thooth'}; from tsamath; excision, i.e. Destruction; used only (adverbially) with prepositional prefix to extinction, i.e. Perpetually -- ever.
see HEBREW tsamath
H6783. tsemithuth
צְמִיתֻת noun feminine completion, finality, only in phrase ׳לַצּ ׳לִצ, = in per petuity, of alienation of land; לִצְמִתֻת Leviticus 25:23, לַצְּמִיתֻת 25:30 (P).