To gradually encroach or appropriate something, starting from superficial or less valuable parts and progressively reaching the core or more substantial parts; to advance step by step through a process of gradual taking, often implying greed or insidiousness.
他起初只是要求一些小小的便利，后来就狧糠及米，提出了更多过分的要求。
At first, he only asked for a few minor conveniences, but later he gradually encroached, making more excessive demands.
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