English

hyperunstable

From hyper- + unstable.

Proto-Indo-European *úp

Proto-Indo-European *upér ‘over, above’

Proto-Hellenic *hupér

Ancient Greek ὑπέρ ‘over’

Middle English unstable

Today it means

adj Exceptionally unstable

Language periods are conventional ranges, not dates for this word.

Etymograph / hyperunstable