The appropriate word is KASLAN not KASOOL.

KASLAN means LAZY for male and KASLANAH for female,
but KASOOL means VERY MUCH LAZY (it became as one of his features)and KASOOLAH for female,

and AKSAL MEN means LAZIER THAN for male and female,and AL AKSAL means THE LAZIEST for male and female.

MUJTAHID is HARDWORKING and MUJTAHIDAH for female
AKTHAR EGTIHADAN MEN means MORE HARDWORKING THAN for male and female.
AL AKTHAR EGTIHADAN means THE MOST HARDWORKING for male and female.