upthrust I. \| ̷ ̷| ̷ ̷\verb Etymology:up (I) + thrust transitive verb : to thrust up; specifically: to push up in an upthrust < before the mountains were upthrust — E.E.Slosson > intransitive verb : to rise with an upward thrust II. \ˈ ̷ ̷ˌ ̷ ̷\noun : an upward thrust; specifically: an uplift of part of the earth's crust commonly with faulting