Sentence:  Klimov put on his greatcoat mechanically and left the train, and he felt as though it were not himself walking, but some one else, a stranger, and he felt that he was accompanied by the heat of the train, his thirst, and the ominous, <WSD>lowering</WSD> figures which all night long had prevented his sleeping. 
Meaning of the word marked with <WSD> tags:  Lurking, skulking, menacing.