Other forms: ultimatums
An ultimatum is a final demand, with a threat if it is refused. Issue an ultimatum, an ultimatum expired, deliver an ultimatum.
The deadline is what makes it one, and issuing it costs you your options: once given, you must either act on it or lose all credibility. The plural can be ultimatums or ultimata, and the plain English form is much the commoner.
1nounultimatumA final demand, with a threat if it is refused.
“His wife gave him an ultimatum: stop drinking or she would leave.”
ultimatum is a demand.
Latin ultimatum means the last thing, from ultimus, furthest or final.
Latin
ultimatus — late, last final
English, today
ultimatum
From Latin ultimatus (“late, last final”), from Latin ultimus (“extreme, last, furthest, farthest, final”).
Etymology from Wiktionary, CC BY-SA