This is a very offensive word. Do not use it. In colonial times, some English speakers used it for an unskilled worker paid almost nothing — porters, dock workers, railway builders — especially in South and East Asia. It treats a person as cheap muscle and nothing else. You may meet it in old books, films, or a history lesson; if you need to talk about that past, say labourer, porter, or the real job. It was borrowed from Hindustani (Hindi/Urdu qulī), “hired labourer.” From there the story forks: it may go back to Ottoman Turkish kul, “servant,” or it may be named after the Gujarati Koḷī community; related forms show up in Bengali and Tamil. Other old words for “low class” or even “shoulder” (the place you haul goods) may have coloured it. Scholars do not all agree. Chinese 苦力 looks and feels like a match, and people here already know that cruel idea; the characters were probably chosen to fit both the sound and the meaning, but the English word did not start from Chinese. What you need is simple: it is a slur. Leave it in the past.