English

rock up

From rock + up.

A compound of rock + up

Old English *rocc

Middle English rocke ‘rock formation’

English rock

Proto-Germanic *upp ‘up’

Proto-West Germanic *upp

Old English upp

Middle English up ‘to a vertical axis’

English up

Today it means

verb To turn up at a place or function spontaneously or unexpectedly, without notice or prior warning.

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