Correct

莫测高深

/ mò cè gāoshēn / 
Strokes

Definition

enigmatic/beyond one's depth/unfathomable

Example

Definition

enigmatic; unfathomable; mystifying

1
Lǎorén
老人
mòcègāoshēn
莫测高深
de
的
biǎoqíng
表情
  
,
ràng
让
wǒmen
我们
cāi
猜
bu
不
tòu
透
tā
他
zài
在
xiǎng
想
shénme
什么
  
。

The old man's enigmatic expression gave us no clue as to what was going on in his mind.