Shinobu displays a rather angry and annoyed aura like she wishes to not be in certain situations. She is rather sharp-mouthed and talks back when she wants to because she believes in always standing up to herself. She is rather cold and doesn't show many emotions and doesn't react to things she doesn't need to react to. 
But, under all this, Shinobu is a kind person and deeply cares for those she loves and respects like her sister and parents who she says that she loves with all her heart.