Sentence:  ... that king on one occasion, April 1535, having to grant a letter of protection in favour of him ‘and his wife and bairns' against Sir Patrick Hepburn of Wauchtonne and thirty-four others for ‘<WSD>umbesetting</WSD> the highway for his slaughter.' 
Meaning of the word marked with <WSD> tags:  To block, obstruct; act detrimentally toward.