吞 (tūn) can mean 'to swallow' but with a sense of gulping down whole or engulfing, whereas 咽 (yàn) focuses on the physical act of swallowing down the throat. In the business sense, 吞 implies a forceful or complete takeover ('gobble up'), while 接手 and 接班 are neutral handovers of duties, and 并购 is the formal term for M&A.