Etymology of ‘pre-emptive’ is used.
Empt or emptive does not exist as a word, and I suppose never has.
Do I deserve the Pre-empt in OED?
Why do we call empt? What does the origin of the pre-emptive term mean?
Late 15c. Exception (n.) later 15c. A “thing bought,” noun of action from past participle stem of emere. Originally used to describe something being offered for purchase to a
group or individual before being offered publicly.
“Pre-emptive,” as we know it, seems to come from the Latin Verb emption -, emptio, from emptus (past participle of emere to buy). See the definition here.
The wikipedia entry of Preemption right states that this usage comes from an existing property in preference to any other person… usually referred to as a right of first refusal. ” It seems as though “preemptive” began as just meaning “right to first refusal” and morphed into a more general “right to first action” as time went on.