?放松

... hide nor hair 踪影；痕迹 let one's hair down 放松 a hair to make a tether of 小题大做的借口（尤指借他人偶尔失言等故兴起的轩然大波） ...

?放松一下

Let one's hair down放松一下 let the cat out of the bag泄漏了机密；泄漏了风声 ..

?无拘无束

Let One's Hair Down(无拘无束), 此释义来源于网络辞典。