at the slope

(Military)(of a rifle) held with the barrel on the left shoulder and the butt in the left hand

(军)（左肩）扛枪

slope arms

(Military)hold a rifle at the slope

(军)扛枪

slope off

(informal)leave unobtrusively, typically in order to evade work or duty

(非正式)悄悄溜走（尤指逃避工作或值班）

the men sloped off looking ashamed of themselves.

那些人悄悄溜走了，满脸羞愧的样子。