Hard

kıyın

(requiring a lot of effort to do or understand)

sert

(resistant to pressure)

sert

(of water, high in dissolved calcium compounds)

zor

(requiring a lot of effort to do or understand)

çetin

(requiring a lot of effort to do or understand)

sert

(with much force or effort (related to act of think))

sıkı

(with much force or effort (related to act of think))