If you take the weight off your feet/legs, you sit down, especially after standing or walking for a long time.

(長時(shí)間站立或行走后)坐下歇歇腳，坐下喘口氣

You must be exhausted after all that shopping - sit down and take the weight off your feet!

逛了那么長時(shí)間的街你一定累壞了——坐下歇歇腳吧!

Here, take the weight off your feet and I’ll bring you a cup of tea and a biscuit.

來，坐下喘口氣，我給你拿杯茶和餅干來。