Correct

失手

/ shīshǒu / 
Strokes

Definition

a slip/miscalculation/unwise move/accidentally/by mistake/to lose control/to be defeated

Example

As a Verb

make a slip of one's hand; accidentally drop sth/hurt sb

1
Yīnùzhīxià
一怒之下
  
,
tā
他
shīshǒu
失手
dá
打
le
了
tā
他
de
的
lǎobǎn
老板
  
。

In a fit of rage, he struck his boss accidentally.

2
Shīshǒu
失手
dásuì
打碎
le
了
chábēi
茶杯

accidentally drop the cup and break it

As a Verb

lose (a game) unexpectedly; be defeated unexpectedly