miser; grasping person
A person who is stingy or tight-fisted, often reluctant to spend money or share resources. The term carries a negative connotation.
He's a miser, so he never treats anyone.
あの握り屋は給料が上がっても生活を変えなかった。
That grasping fellow didn't change his lifestyle even after getting a raise.
Compound of 握り (nigiri, 'gripping' or 'holding tightly') and 屋 (ya, suffix for a person with a certain trait). The image is of someone who holds onto their money tightly.