‘To reave’ is an archaic verb meaning to carry out raids for plunder, or to rob somebody by force, with the past tense of ‘reft’.
There is a vestige of this in the still current words ‘bereave’ and ‘bereft’, used mostly in the sense of grieving for someone who has been lost to you; presumably the implication is that you feel you have been robbed of their presence. A ‘bereavement’ is a gentle way of referring to someone you love having died.
‘Nobody knows / where these reavers from hell roam on their errands.’
Source: Seamus Heaney, Beowulf, p. 7