Sentence:  ...his lordship was out of humour. That was the way Chollacombe described as <WSD>knaggy</WSD> an old gager as ever Charles had had the ill-fortune to serve. Stiff-rumped, that's what he was, always rubbing the rust, or riding grub, like he had been for months past. 
Meaning of the word marked with <WSD> tags:  Temperamentally rough.