放开

to let go / to release

to put / to place / to release / to free / to let go / to let out / to set off (fireworks)

to open / to start / to turn on / to boil / to write out (a prescription, check, invoice etc) / to operate (a vehicle) / carat (gold) / abbr. for Kelvin, 開爾文|开尔文[Kai1 er3 wen2] / abbr. for 開本|开本[kai1 ben3], book format

to have free rein (idiom)