(N/A) $1$. Impure Semiconductor: An impure semiconductor,also known as an extrinsic semiconductor,is a semiconductor material to which a small amount of specific impurity atoms has been added to significantly increase its electrical conductivity.
$2$. Doping: The process of deliberately adding a controlled amount of impurity atoms to a pure (intrinsic) semiconductor to modify its electrical properties is called doping.
$3$. Dopant: The specific impurity atoms added to the pure semiconductor during the doping process are called dopants. Examples include elements from Group-$13$ (like Boron) or Group-$15$ (like Phosphorus) of the periodic table.