หนัก(nàk)

heavy (weight)

Having a lot of weight; difficult to lift or carry.

serious; severe

Serious in degree or intensity (e.g., severe illness, heavy damage, grave situation).

heavily; severely; intensely

To a great extent or degree (e.g., rain heavily, be punished severely, study intensely).

difficult; tough (mentally/physically demanding)

Hard to deal with or very demanding in effort or impact (e.g., tough class, demanding workload, heavy topic).