空拳的英文：
an empty fist

参考例句：

A hollow fist and bare hands
空拳赤手

empty是什么意思：
adj. 空的，空洞的，空虚的
v. 倒空，把…腾出，撤离
n. 空物

The bookshop was empty.
书店里没有人。

The river empties into the ocean .
这条河流入海洋。

He that is full of himself is empty
自满者无知

The theater was half empty.
剧院的座位一半是空着的。

Empties are not taken back.
不退瓶子。

fist是什么意思：
n. 拳头；笔迹；掌握
v. 紧握，握成拳；用拳打

double one's fists
握紧双拳

He writes a good fist.
他写得一手好字。

His fists were clenched tight.
他紧握双拳。

He doubled up his fists .
他握紧拳头。

I raised a fist to slug Eddie.
我举拳重击埃迪。