Correct

干脆 vs 索性

/ gāncuì vs suǒxìng /
Strokes

Formula

1
干干脆脆

Definition

干脆 as an Adjective and 索性 as an Adverb, which both means [straightforward; resolutely], means "to act in a straightforward way or even going to the extreme".

Example

When 干脆 is used as adverbials, it can be replaced by 索性.
Here, 干脆 is more colloquial.
1
rán
既然
men
他们
liǎ
néng
zuò
合作
  
,
gāncuì
干脆
  
(
suǒxìng
索性
  
)
fēnkāi
分开
zuò
  

Now that they cannot cooperate, you'd better separate them.

2
jīng
已经
wǎn
le
  
,
gāncuì
干脆
  
(
suǒxìng
索性
  
)
zhù
宿
zài
zǒu
  

It's too late, so you'd better stay here for the night.

When used as an adverbial, 干脆 sometimes means "not to mince one's words"; 索性 cannot be so used.
3
Gāncuì
干脆
huà
  
:
ying
答应
ying
答应
  
?

Please give me a straightforward reply: yes or no?

Since 干脆 is an Adjective, it can also function as an attributive, predicate, complement, etc. It can be reduplicated into 干干脆脆 and has a wider meaning (straightforward, point-blank); 索性 cannot be so used.
干干脆脆
4
shuōèr
说一不二
  
,
zhēnshi
真是
gāncuì
干脆
de
rén
  

She is very firm and straightforward. (attributive)

5
zuòshì
做事
gāncuì
干脆
diǎnr  
点儿
  
!

You'd better be snappy! (predicate)

6
de
huà
shuō
de
gàngāncuì
干干脆
cuì
  

His words are very straightforward. (complement)