One making a stir has to deal with blank look (5,4)
I believe the answer is:
poker face
'look' is the definition.
(I know that poker face is a look)
'one making a stir has to deal with blank' is the wordplay.
I cannot really see how this works, but
'one' could be 'ace' (ace has a value of one in some card games) and 'ace' is found in the answer.
'stir' could be 'poke' (poking is a kind of stirring) and 'poke' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for poker face that I've seen before include "Inscrutable expression assumed to conceal emotion" , "unreadable profile" , "Countenance giving nothing away" , "Impassive expression that hides one's true feelings" , "Expressionless visage, useful when playing cards" .)