师傅(shī fu) - master craftsman, a polite term for a skilled worker in Mandarin

师傅 (shīfu) started as a title for a master of a craft, the person an apprentice was bound to, and it still carries that respect for skill learned by hand: a cook, a mechanic, a tailor, a carpenter.

Its more useful modern job is as a form of address. If you need to speak to a taxi driver, a workman, a delivery rider or a stallholder whose name you do not know, 师傅 is the safe, friendly opener. It works for a stranger the way "mate" does in Britain, but with deference rather than familiarity, and it is one of the fastest ways for a learner to sound polite instead of stiff.

The trap is its near twin 师父, pronounced identically. 师父 is a master in a lineage: a martial arts teacher, a monk, someone you are formally a disciple of. Write 师父 to your taxi driver and you have promoted him to spiritual guide. In speech the difference is invisible, which is precisely why it catches people out the first time they have to type it.