Sentence:  As they traveled along L.R. 33060, one of the passengers mentioned he had to <WSD>relieve himself</WSD>, so Barrett stopped the car along the berm of the road, which, unbeknown to the travelers, was directly adjacent to a strip mine. 
Meaning of the word marked with <WSD> tags:  To relieve oneself of a need to excrete waste: to urinate or defecate.